Hi Rob
Welcome to the Forum
The 1 series you owned was it a diesel? I would at a guess it was a 118d or 120d, extended service intervals really caught many N47 engined BMW owners and BMW out. The engines that were getting oil changes seemed to fair much better
The engine in the E46 is different N46 at the low-ish mileage 55k oil and filters would always be my priority to give the engine a better chance at a long life
Lots of things effect ball joints and rubber bushes. Just helped a neighbour with a suspension rebuild he got a complete kit for £120 Lower wishbones track control arms and Anti roll bar links took around 3 hours with tea and biscuit breaks. Check the internet or your local motor factors for costs then use it as a negotiating point
Good Luck with the purchase
Dave