i had the whole exhaust system custom made for suit the power output of the car and it helped to free up the throttle response a lot!
this along with an induction kit will help your car go quite a bit better.
I put the group n exhaust on my 1989 1.7 8v, considering the cheapness of price (£90 for middle and rear) it was well made and fantasticly loud! Made a difference to throttle response and genneral driveability.
Dont buy one if you are shy and retireing as you certainly attract attention.
If you cant justify a full stainless steel system you've goota get one of these babys!