I got Perrin 3' downpipe in my evo right now with HKS 264 cams and Catback. I wonder if I put in HKS 3' downpipe, will it make a better quality sound?

PS: HKS cams + HKS downpipe + TTP testpipe(muffler) + HKS catback (Hi-Power)
WILL IT BE BETTER?

 

Changing from one 3" downpipe to another won't really make of a difference. If you want a different sound, your best bet is swapping mufflers or adding/removing inline resonators.

 

yup! its the muffler and resonator that makes the difference in sound, not the 3" downpipe!

 

hahah you know.. it looks cool tho. HKS upper ICP, HKS DOWNPIPE, HKS CAMS and HKS Catback.. BLAH HELP OUT! (post what u think)

 

It's not going to accomplish what you are looking for. What is it about the sound that you dislike? Too loud? Too raspy? Too deep? Buying something just to say you have it is a waste of money imho.