Welcome to the forum.

Your best bet is to have a look around the mk4 section to find common faults etc. I dont know too much personally about the mk4, but it seems to be the 2.0 8v engines that have the reputation for drinking the oil. You need to look for the 1.8 20v or if you find an older one for your price range get a 1.8 20vT. Put some questions in the mk4 section and they will be answered for you.
But for either the 2.0 or 1.8 20v dont expect blistering performance.
