exhaust system

[paul_k10_Lx]

ive got a 4 - 1 on the car with the carbs but the rest of the system is pretty poor

the outlet ov the manifold is about 1.75" would it be best to keep this size back to the back box or will goin bigger open it up a bit.

It will be going to a nice 3" inward rolled tipped Back Box

 

[SammoHung]

advice that ive received for my 988cc is not to go above 1.75 pipework otherwise N/A performance will start to roll off

Bigger pipes will benefit while on boost though....i guess its a bit of a trade off trade off.

Personally though I would hate to sacrifice NA

Would be good to hear from others on this though too