So I did a few calcs. They're really similar. The MN12 has very consistent ratio changes, where it drops 70% up through 4th. The MM6 has a bigger 1-2 drop, but tighter ratios elsewhere. I like the MN12 personally. The ratios are overall greater. I'd put a 3.54 behind it, or a 3.69 with DR's. Those both make for a pretty agressive 1st gear with 375tq and run out way over 50mph (i think). I don't have my calcs with me, but 6th will probably run out over 250mph, which isn't really relevant except that it implies a nice low cruising rshared_pm in 6th.