However the E46 platform...esp that 3.0l motor is REALLY REALLY reliable, requires very little maintenance. When you need parts there are lots of sources AND even if you want OEM parts Tisher bmw sells wholsale parts online.
Yes you'll need to plan on doing control arm bushings and trailing arm bushings, if you buy a coupe the window trim WILL fall down on a summer day, it's not going to be trouble free but our old E46 325 was the most reliable, enjoyable car I think we've ever owned. You never had to worry about the thing, just get in, drive and enjoy.
"regular", older E46 cars are stupid cheap too for what you get. I think the ZHP 330 would be a great choice though despite the premium you'll pay for it.
Andy