120+ miles usually is not a problem, but it depends on how the engine has been looked after. There are a number of owners here that have cars with their original engines fitted, boasting well over 200,000 miles, and still going strong. I myself had an old 1980 Audi 80 GLE, 1.6 injection, which had pretty much the same engine as the Golfs, and I sold that with 190,000 miles and still going strong back in the early 1990's.
If the engine puffs out a bit of blue smoke, then attention will be needed. If black smoke, then a good tune up will usually sort it. If steam, then the head gasket may need attention.
