okay well i've had my IS for almost a year and I think its about to make my car alittle faster. I was considering what should come first: brakes, suspension, intakes, exausts, and body kits. Anyone with any suggestions what should come first?
Well, relative to the IS250, you have better brakes and a more powerful engine. So those may be less of a concern depending on your needs.
I don't know if the Lexus community has established a proper definition of ISx50 Stage 1, Stage 2 etc… modifications but anyway, here I go.
Stage 1 mod for power would be an intake and axle-back exhaust – Some power but mostly sound.
Stage 2 mod for power would be Stage 1 plus a full exhaust IMO.
Stage 3 mod for power would be Stage 1 & 2 with NOS IMO.
Stage 4 mod for power TBD.
I would lump suspension(lowering), body kits and wheels into one grand package as it all has to gel together. Also you would want to pay attention to the rim clearance around the brake calipers if you intend to upgrade.
I am not a big fan of the appearance mods but ‘red-outs’ for the rear brakes seems subtle enough for my taste. Also changing out the headlights, fog lights, parking lights etc… is cool but again I favor subtle changes. Everyone has different tastes so.
Just remember, once you start moding, its very hard to stop!!! Just a friendly warning.
The best way to make an IS350 significantly faster is to trade it in for an IS-F. Seriously.
Failing that you have 3 options-
Find an LMS supercharger (they don't sell em new anymore) and you'll spend about $6000 bucks for about 40 rwhp. The IS-F remains a better deal compared to this IMHO.
Put on your own nitrous kit. There's a guy running a 55 or 65 shot, it's relatively cheap, and will add probably as much as the supercharger kit for much less money. Risk blowing your $10,000 engine on your own though.
Put on a set of Mazzuri headers. Gains are 25/30 on a 250, so should be better on a 350... you won't pass a visual inspection anywhere in the US though, but cost is under $1000.
Intakes and exhaust will be a lot of money to make your car louder, and not much faster. Your choices here are a Joe Z pipe which is the best intake option at only $109 or so for the 3-5 hp you might gain on a perfect day from an intake on a 350. For exhaust if legal isn't an issue one of the full (cat-deleting) exhausts will run $1200-1500 and add maybe 10-15 hp... if legal IS an issue then an axle back like the tanabe will be around 600 bucks and add maybe 5-7 hp.
For suspension the F-sport stuff (shocks, springs, swaybars) will all be out next month, I'd probably wait for the reviews of that stuff to start rolling in.
For brakes, again there's an F-sport kit, but you might want to read an article titled pulp friction about what actually stops your car before messing with parts of a factory brake setup.
Body kits don't make your car any faster of course, beyond making your wallet lighter