yes and no mate, in the end, we drive turbo cars, the exhaust needs get to out, the better you can make it flow the more efficient your engine will be.
3.5-4ich exhuasts seam to work on GTRs.
i had a 4inch exhaust on my gtr, it was loud... So i did alot of research into how the exhaust system works, and this is what i came up with to find that happy medium.
The way i see it, the exhaust is more dence when its hot, therefore it needs more area. So it needs to be bigger closest to the engine and can become smaller as it gets further away.
my exhuast consists of,
* Tomei dumps,
* Twin tuned length 3inch front pipes
* Into a 4inch merge,
* The 4inch carrys for 350mm than falls into a 4-3.5inch tapered cone which is disguised as a cat (cough cough)
* Than from the "CAT" it flows into a Ti Tomei Catback.
So in the end i have around 700mm of 4inch...........
This equals a bullshit high flowing exhaust system, which is not that loud. (considering)
pic of the front pipes i made, they tuned length within, 20mm