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I was wondering if these headers are any good for the IS300. Ive heard that the Mazzuri may be the best for the IS3 but I also heard it is the loudest and most expensive. I would just like to get some hp gains and maintain a low sound with my SRT intake and Tanabe Hyper Medallion catback.
 

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I don't think anyone has ever actually done a good test between the OBX and the Megan.

The only thing I know is my OBX made a noticeable difference and the midrange is wonderful around town. The Megan is about 3lbs heavier but is also cheaper.

Toss up between the two truthfully.

The OBX will definitely make your car a little louder, though at cruise speeds and at warm idle my car is no louder inside (according to an accurate dB meter) than it was stock.... through my JoeZ intake and WS2 Exhaust.

Hope that helps you. I will tell you that the 2nd bank O2 sensor is a tight fit against the firewall. I have read stories of either having slight fitment issues. I think the megan is most popular as it is cheapest by a few bucks.
 

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where can i buy obx headers and how well do they fit onto a megan ypipe?
 

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Almost everything from Megan is crappy thats why your most likely to pay less. Ill give them credit though if you call them because your having some kind of issue with their parts they will refund you in full. They know that the o2 sensor doesn't fit though & that their gaskets are of poor quality. When i called and complained about the o2, he said that my dealer should have told me about that but they suggest to bang in the part of the firewall so that it would clear with a hammer... I found a toyomoto alphawerks header and y-pipe a week later. 4get that!!!
 

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Almost everything from Megan is crappy thats why your most likely to pay less. Ill give them credit though if you call them because your having some kind of issue with their parts they will refund you in full. They know that the o2 sensor doesn't fit though & that their gaskets are of poor quality. When i called and complained about the o2, he said that my dealer should have told me about that but they suggest to bang in the part of the firewall so that it would clear with a hammer... I found a toyomoto alphawerks header and y-pipe a week later. 4get that!!!
i already bought megan y-pipe and i heard nothing but good things about the y-pipe. i havent bought the headers yet and i know of the o2 not fitting. that wasnt my questions though (and sorry to hijack the thread). my question was how well does the obx headers (or alphawerks) fit with megan y-pipe and where do u buy them?
 

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it comes with the y-pipe to? and do u smell it in the car? i dont mind it outside but if i drive and smell ass ill just day fuck the headers and use my money elsewhere
 

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Does anyone with obx headers get exhaust fumes into their car? I get them when I open any window in the car. I been having the headers for a while now and didn't mind at all but im just wondering if this happens to anyone else.
 

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Does anyone with obx headers get exhaust fumes into their car? I get them when I open any window in the car. I been having the headers for a while now and didn't mind at all but im just wondering if this happens to anyone else.
fumes in the car ............with windows down then you can maybe smell it from outside..if you wanna rid some of the smell had an high flow cat to the y-pipe.
 

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i wouldn't bother with the obx headers, a friend running an aem intake, apexi exhaust and obx headers isn't faster than my car and all i have is a srt intake and dragger II cat back...get the mazzuri you def want the most hp u can get from ur headers.
 

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Whenever you remove restrictions in the exhaust you're going to get an increase in HP but a possible decrease in low-midrange torque.

With this said OBX makes both a long a short runner header. I would be surprised to not see a HP increase in both however, a substantial increase in HP and torque? I'd be surprised. The only difference is going to be the "butt" dyno.

Oh, and our cars run rich, hence the fumes.
 

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so are headers even worth it?
 

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The fact that someones car is slower than someone else's could have to do with any number of things...

For example, the base model IS300 is at least 100lbs lighter if not 150lbs lighter than the loaded up version.

The 2001s have different tunes from the 2002+, some IS300's got the upgraded tune from the Lexus dealer in I believe 2003 or 2004 ...some didn't. Some have CA emissions standards and some weren't originally sold in CA so they have a different tune all together.

Some people fit wheels that are heavier than stock, some fit wheels that are lighter.

Then there's drag from body kits or body modifications, driver, the actual maintenance and tune of the engine. There's even more variables... perhaps the tires one car are heavier than on the other. Then there's mechanical differences.... when the engines were new they weren't all built EXACTLY the same. Very close to the same, but each engine is going to vary by a few horsepower up or down (nothing too crazy, but a few here and there).

On my car even, the stock header was welded together by apes... One bank had SIGNIFICANTLY less inside diameter than the other bank. I know not all IS300s had that huge detriment to performance.

By some of these posts I'd guess you might as well not bother modify your car at all.... which is one way to look at it.

Yes, the headers will do -something-, probably make the car sound better, and quite probably gain you 10-15hp. Is that going to change your life? no. But if you want just a little extra pep... it's not a bad start.

Really, tuning your car isn't worth it period, but you don't do it because it's great value for money or because you want the fastest car on the road... you do it because it's fun for you and it adds just a little something to a car you already love.

I hope that no one in this section anyway expects anything else from what they're doing. If you don't LOVE the IS300 for the car that it is, then sell it and move on to something that meets your needs better. Bolt-ons are more about slight refinements to what you already are pleased with.

As for the fumes - I can smell them with the windows down only and only while sitting still in traffic. They're not very strong, but just buy a high flow 2.5" cat off eBay or from a reputable dealer and have the exhaust shop weld it in. Cost you about $75-100, no fumes, no power loss really (maybe 1-2 peak horsepower), and it'll be slightly quieter ...even though it's not very loud anyway.
 

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i was looking to make the car as powerful as i can without turbo charging. i have a joe z intake w/ a K&N drop in and an HKS carbon ti exhaust. i wanna finish the exhaust so i bought the megan y-pipe and im saving for the headers and token o2 sim. i just dont know what headers i want yet cause if i buy the megan and have to pay to relocate the bung i might as well but an obx or somethin where i dont have to.

believe me i love my IS300. best car by far that i have ever owned. i am learning alot about it but in ways i still have a tiburon mentality cause that was the first car i started modding. but next thing is HKS cam gear srt intake, apexi neo and greddy e-manage ultimate. i was reading somewhere that this would be the best way to start. after all this im goin to get the speakers for my system and then worry alittle more about appearance.
 

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HKS Carbon Ti with OBX header and y pipe will sound deep as hell, but will drone and above 3k revs will not be as deep. You WILL get exhaust fumes back in the car when sitting at a light for a ling time. Will you gain power= hardly at all, i have them and personally i think all it did was shift my powerband to the right. if u want a fast car sell you NA mods and save for boost.
 

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Alright I will go ahead and get the high flow cat. But which exhaust should I go with I was thinking greddy evo 2 is this one considered a cat back exhaust
 

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Alright I will go ahead and get the high flow cat. But which exhaust should I go with I was thinking greddy evo 2 YESis this one considered a cat back exhaust
Yes ---i highly recommend you stick with the stock b pipe and run a axle back with aftermarket header and y pipe to keep rasp and drone down..
 
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