I wish 5th and 6th were just slightly longer in my 135i 6MT. The gears are progressively tighter towards higher gears. That's generally good, but I think they are too close in 5th and 6th. Only 19% between 4th and 5th, and 15% between 5th and 6th. (1.19 : 1.00 : 0.87 for 4, 5, 6)
If 5th were about 0.96 and 6th were 0.82 I think that would negate the need for a 7th gear. I don't feel the lower gears need to be any closer either. 1st is a tire roaster. The engine with a reflash tune still wins against my 265/35/18 StarSpecs in 2nd gear on anything but a prepared drag strip. With such a wide power band, 3rd is still fine. It would just be nice to turn slightly less RPM when I'm on the highways around here with 70mph speed limits. My gas mileage tanks rapidly above 65mph. At 65mph I can get close to 29-30mpg; at 70mph, I get around 27.5mpg; at 75mph, I down to about 25.5-26.0. It's not just the engine speed, air resistance is an effect, and engine speed doesn't help tire loses, wheel bearing loses, etc. so I wouldn't expect miracles, but I think it would help.
2009 BMW 135i, 6 MT, M Sport, DIY DCI, Cobb AP, Apex 18x8.5+9.5, 235/265 Starspecs