Just fitted Nur Spec back box & centre section on a MY02 (with extension pipe) the car also has ITG panel filter & Forge VTA dump valve. Before the new exhaust went on spool up would start around 4k along with whoosh from dump valve. I now find that whoosh starts around 5kish & the kick kinda feels harder almost like there is more resistance in the system. Not sure why but I was expecting spool up say 3.5K & less resistant type of feel. Has anybody got any idea`s or experienced this before.

Cheers