i was forced to upgrade as well and i just did it. i went level 10 which everybody is putting down but so far no issues... i have unlimited miles warranty with it.
thing that i had to send my trans to the us as well. i have checked ALL possible solutions in europe and at the end there was none....
07 335i AT - MOTIV 750 - COBB (Custom Cobb mapping by MOTIV) - BMS PI - JB4G5 - Okada Coils - NGK 5992 Plugs - Helix IC - Snow Stg. 3 - Stett CP - Custom midpipes with 100 HJS Cats - Bastuck Quad - PSS10 - QUAIFE LSD - BMS OCC - Forge DVs - AR OC - ALCON BBK - M3 Chassi - Dinan CP - Velocity M rear Toe arms - Advan RZ-DF - LUX H8 - Level 10 AT upgrade