1996 E36 318i 180,000 km!
Engine is an M43
Best of the worst I'm sorry!
Look out for:
Oil leaks between cyl head & block (head off to fix)
Oil filter housing to block leaks
Radiator expansion bottle leaks (looks like part of the radiator but it's not - prone to cracking $375 + fitting)
Water pump has a plastic impellor (prone to de-bonding off shaft)
Engine has 3 x plastic water fittings (prone to becoming brittle and failing)
Front lower caster rod bushes (check tyre wear - $350 for bushes alone + fitting)
Tailshaft rubber coupling (guibo) prone to failure.
I'd avoid 318's like the plague! If you want a 3 series look at the 323 (M52 6 cylinder) much better reliability.
(I previously worked for Auto Classic)