will a stock exhaust in a 99 civic si b16a hurt my turbo? i'm gonna boost 7 psi. i have a round muffler straight through flow design. i was told by a sales rep in a performance shop that it'll decrease the life of the turbo.
also, do i have to clamp down the silicon hoses that go from the internal waste gate to the turbo & gauge etc. thanks

 

i have your same car with my stock exaust except for a straight through muffler and nothing has happens to my car and ive been boosting for like 2 months.

 

It wont hurt anything, but it wouldnt hurt to go with bigger (2.5"-3") pipe size to uncork that bitch on the top end.
clamping your wastegate signal line on both ens is always a good idea (if fits kinda loose).

 

thanx for the good replies, i'll keep the stock exhaust tubing for now til i recover a little from the cost of all this stuff. there's a local muffler shop that'll install their own mandrel bent 2 1/2" cat back w/o muffler for $120
not bad, but ima wait another month after the hmt install