At 127K, I would replace the water pump and thermostat. They should be replaced in 3s and 5s every 60K. At 120K, I would replace all of the filters, cabin, fuel, and air. I would replace the spark plugs also. I would have a gear and diff fluid changed every 30K. Coolant flush every 2 years and brake fluid flush every year. Oil change every 5000 miles along with the oil filter.
The V8 engines have problems with the clutch, meaning that BMW put in a clutch that is too small for the V8. This occurs in the 540 and the M5. The trannys can be good, but I would have them checked for metal particles in the tranny fluid. This would indicate worn synchros.
I think the 540 maintenance and the 3 series are similar minus the clutch issue.
I prefer the 5 to the 3. Parts for the 5 are more expensive than the 3 and the 5 is more expensive to mod. You can't go wrong with the V8 engine.
PM the VIN and I can run a carfax for you.