The 540i is a fine & fun car. The acceleration is better then most cars on the road with the HP and good torque. Mine is black, w/ black leather interior, and chrome 18in Hamann deep dish rims, w/ 40 series tires, lowered about 1.5 inches, w/ angel eyes conversion, cone air intake, & custom exhaust. It looks pretty good for a 10 year old car. It handles well in corners, but you can tell that it is a little bit nose heavy due to the V-8 in the front as you can break the rear loose when coming around a corner.
Acceleration, exterior style,dual-zone temp control, brakes work really well.
Gas mileage, cup holders break all the time (just glue then shut with some black foam & don't use them if it breaks), sunroof motor won't tilt roof, door handles will break as they are made of hard plastic, engine valve gaskets will need to be redone, pixels underneath speedo will burn out.