I checked up on these a while back but being a tight-arsed Northern git I never bought 'owt as mine is not yet worn out.
You can replace the cat with a bit of pipe with square flanges on it, I did but frankly didn't notice much difference (Don't buy one from Co-orsport it doesn't fit)
The rest of my exhuast is standard and probably tighter than a nuns-chuff so that may explain the lack of any improvement.
The only systems you can buy of the shelf are super expensive Jap stuff. Eg a HKS cat-replacement is in fact a full pipe from the turbo down and costs about 300-odd quid - That was from Mark Shead at MAD (adverts in the club mag). The rest of the systems are blitz.HKS, etc.
No UK companies do replacement systems for the Early Evo's
You have another choice, which is the route I will go when my exhaust does die. Get one custom made. Turbo to exit. Pick a rally -exhaust specialist and they should be able to tune it for torque. Some of these places will already have jigs for Group N (or maybe group A) Evo 3 exhaust systems. They *should* work on the E1 - but be prepared for a few hic-cups just in case http://18.104.22.168/graphics/biggrin1.gif border|EQU| 0 align|EQU| absmiddle >
Anyway, what do you want an exhaust for - haven't you spend enough already [img]http://22.214.171.124/graphics/biggrin1.gif border|EQU| 0 align|EQU| absmiddle > on your spoilers/etc/etc