Originally Posted by
Sp3no
I would not bother with a sports cat either, i know 2 people who had them fitted and thier cars failed emmisions test, the pumaspeed ones are particularly bad.
As for retarding the timing on the exhaust cam with a vernier, expect anything from 5-10bhp.
how much are u usually retarded by? i can set it up on a rolling road so can find where its best but would like a starting figure.
do they loose low end grunt also?