Looking at buying 1st gen/Mk1 TT-what are known issues?

Have owned and maintained a 2008 S6 for last 5 years and a 2009 A4 for 3 years before that.

Considering buying a 2001 TT Quattro coupe 225 turbo 6 speed manual from a trusted friend. He and his family have owned it since new. I know very little about the car at this point, but he is sending me a copy of all maintenance records. We’re also having a PPI done by an independent Audi mechanic.

What inherent, known issues are there with this model? Want to know what I should pay special attention to in the records and PPI.