Id go for the Audi.. They depreciate like a stone so one should be cheap but they have a 4 year maint included warranty so you might be able to get the dealer to bring it up to a clean level if there is some warranty left. They also give you a loaner while they are working on it. You say you want to delay mods so wait for the warranty to run out...

The 1.8T has a lot of mod potential.