Well I went from 15.3 down the quarter with a stock zaust system to 14.7 just from a turbo back 3 inch system.
I only have 4 bends in the whole system, and a *cough* high flow cat and well the tip, hmmmm lets just say it looks like it was home made, BUT the whole system is 3 inch and I bought it for a steal, BEST thing is, (and I have no idea why but) there is very very very very little drone, which all but dissapears when the windows are up, which is great.
I have no resonators, just a 3 inch dump, high flow cat. other than that the whole system is basically straight with one bend at the top of the dump, one bend at the bottom of the front, one small 2 degree bend after the cat and one 2 degree bend where it passes over the diff.
Now here's where the story gets interesting, I did whack on a mates HKS super dragger cat back with the rest of the stock system, and it was LOUD, way louder than with the current full system, stiil another good thing about this current system, Very nice noises under load
I am not proffessing to know why, just the results.
Plus I have dyno's of before and after with JUST the HKS super dragger, added 15rwkw, and I did not do anything but add the HKS super dragger cat back on the same dyno.
I do not have dynos for before and after I have put this full system on though, yet
Anyway hope that helps, I dont know why it would and I think I have had way too much coffee today which is why I am still typing so I'll just go whore somewhere else..............