I've been driving my '97 540 since March '09 with zero issues.
When I bought the car last year (92,000 km) I changed out the spark plugs, coolant, oil, oil filter, fuel filter, air filter, cabin filters, diff. oil.
Since then, only oil changes, and wiper blades.
No shop time - all done in my garage. One of the best, least costly cars (other than gas!) I have ever owned.
'00 Viper - Steel Grey - stock....so far.
'97 540i - The daily grind mobile
'87 Porsche 930 (B&B exhaust, SC cams, Garrett hybrid turbo, adjustable boost control, Andial fuel enrichment - 400 h.p.) - SOLD