NA you lose some bottom end torque going with 3 inch with no cats and header. No significant power gain in hp. Proven already. Other than that louder noise levels. Most go with 3 inch as a temp till they get a turbo. So NA only 2.5 would be the best over all.
Yeah my original plan was turbo which is why I got the 3". One thing to note is because the 3" supports so much flow there is no backpressure which puts all the strain on your cat. This has caused my cat to start to blow to bits slowly so be aware this will destroy your cats.
So having essentially a straight pipe in terms of flow definitely hurt my low end torque a bit. Don't get rid of your resonator, your resonator is what helps reduce rasp and drone. Your muffler will dictate how your exhaust sounds and how loud it is. Keeping your cat will help keep some back pressure the engine likes.
Feel free to copy my setup I love the sounds and the power isn't terrible the vibrant stuff is really high quality and affordable. Fyi the exhaust seems to rattle everything so be prepared for a rattly interior. I would recommend you put the resonator in as it really helps avoid the typical is300 rasp. Sounds very deep and angry with a hint of cam. It'll be interesting to hear what it sounds like with headers.
Way back in the days of the forum. I do not know if they are still posted from old members that are not active anymore. A lot of that stuff was not hosted by the site. So if they deleted it. It would not show anymore.
