Re: 1990 Coupe Quattro 170K
Is it a 20v? If so check out www.20v.org
A lot of the stuff applies to 10v as well..
Parts, try VAGparts, eurocarparts and German Swedish French (GSF).
20v CV joints are particularly expensive, coupe window regulators are also expensive. As per 20v .org, check the 'bomb' (not 10v) also check handbrake is effective both sides and releases properly, if not recon calipers needed. 20v should have green hyd oil in power steering/brake assist system, not red ATF. If red walk away, seals will breakdown...