You're most "safe" aftermarket tunes are the BMW PPK and DINAN. Both match BMW's factory warranty and you can drive into any dealership on the off chance something goes wrong (which are slim to none), and actually have a chance to get support for it. Neither are cheap and they are flash tunes, which essentially means no resale parts (except a few dollars more paid an enthusiast might pay on a private sale for a PPK or DINAN car).
My only problem right now with my DINAN stage 3 is that I MIGHT have lost it when the dealer had to re-program my software to fix a flaky brake sensor, but I am worry free, because I get free re-flashes from any BMW DINAN dealer- for the life of my ownership of the car.
Pay to play.
Last edited by Dark_Knight_335; 08-02-2013 at 10:05 PM.