Well, that display will set you back $500 or so (the led one--mine gradually faded away, but iit is pretty easy to replace)
THe other display---try resetting the computer---you hold in both buttons below the guages until you hit a number and when "unlock"comes up you enter the last 4 #'s of your vin to unlock---(it was 19 plus my vin on mine---not sure about the 740, but that info is pretty easy to find online)
Yeah, the 540 was basically my fave too(for a car) and the only car I ever felt really comfortable driving more than 120mph ---gotta love being at 135 and knowing you've got plenty more room.