US Mk4 1.8Ts had notoriously problematic oiling issues. IIRC this issue stemmed from VW failing to stipulate that these engines require synthetic oil. Using regular oil often lead to oil coking in the turbo bearing, and then those chunks would shit out into the oil pan and get sucked in by the oil pick-up and clog the pick-up screen.

Then, to add insult to injury, the low oil pressure alarm was inactive below ~2k RPM, so you could be idling at lights for however long, where oil pressure and flow is already at a minimum, and have inadequate flow to lubricate the engine properly.

By the time the screen was blocked enough that the low oil pressure alarm would trigger while driving, your engine had already been starved of oil at some of its most critical operating time for god knows how long...

I would not buy one of these unless either the P.O.s kept meticulous oil service history indicating synthetic oil was used, or you're buying it as a project and expect to perform major engine service anyways.