I will comment on the 330i (been there, done that, got the T shirt).
Agree with Adi, as soon as you get it, refresh the cooling system. 12 to 15k.
Radiator, thermostat, expansion tank, hoses.
Then inspect your ccv/ pcv for possible air leaks. Budget 5 to 6k to replace it together with the 4 hoses if needed. (Misfire on cold start up, progressively getting worse when it is really cold outside).
Also, at that age, ask whether the Disa valve has been replaced already. If not, 5.5k from the agents and 10 minutes DIY.
Oil change you can easily DIY, 6,5l oil and a filter will set you back about R800,00 if you do it yourself. Can't remember what I paid for an air filter, but it wasn't a fortune at all.
Spark plugs were about R80,00 odd each.