S3 back box onto an '99 A3 1.8t sport?

I don't think it is. Thanks to the 4wd system, the back box on an s3 runs across the back of the car. From memory, the A3 runs down the car. I also suspect that the pipe diameter might be different.
 
thanks for the reply. Is there a well recommended upgrade for the standard exhaust? I dont want anything too loud or obvious... understated is the key... to match the debadged rear, standard exterior and the ahem... 210bhp under the bonnet ;)
 
a golf mk4 exhaust...jetex are good or miltek

or justa custom made one
 
Speak to the boys at MIJ Permorfance, they are pretty good and know what they are talking about, look for mazzy on the forum, i believe he may be able to help you out as he works there...
 
thanks Nilz... i'll look him up and hopefully have a chat with MIJ.