Re: RPM in 6th gear at 80 mph?
I also have both of these cars, same years. What colors do you have? The 540i has a 2.81:1 differential gear ratio whereas the M5 has a 3.15:1. This 12.5% difference translates into less speed for any given rpm and gear. It also means more getup and go for the M5. I do sort of miss the older gearing, which felt more like autobahn gearing.
2002 M5 Carbon Black/Caramel Extended Leather
NAV, PDC, DSP, Dinan Strut Tower Brace, Valentine One, K40 Laser Diffuser, Bluetooth Telephone, Debadged.
1999 540i.6 Biarritz Blue/Sand-Beige
M5 Front Bumper, Clear Corner Xenon Angel Eyes, Clear CELIS Tail Lights, Clear Side Blinker, M5 Grills, 18" Staggered M-Parrallel Style 37 Wheels with Dunlop SP Sport Maxx Tires, 17" Staggered Radial Spoke Style 32 Wheels with Michelin Alpin Sport Tires, M5 Rear Stabilizer Bar, Rogue Transmission Mounts, Rogue Short Shifter & Wieghted, Selector Rod, CDV Deleted, Stop Tech Stainless Steel Lines, Custom Brake Air Ducts, Dinan Engine Software, Evosport Underdrive Pulleys, Hamann Sport Muffler, Valentine One Radar/Laser Detector, Stealth One Interface, Debadged.
Retired: 1997 540iA, 1994 540iA