I put one of their tuner secondarys on my 06 M7. It took a bit to get it dialed but with the help of a very knowledgeable person here on the 4M I got it running prime. Its a night and day difference compared to the stock setup. It isn't as "bolt on" as STM makes it out to be. I had to pound a few small pieces back to ensure that it wouldn't rub at full shift out as well as I shimmed the engine over with few 3/8" washers to get the correct belt alignment.
In terms of perfomance. It shifts in and out AWESOME. Say in some tight trees where I'm on and off the gas, it makes the sled just pull amazingly well. Setting it up is really easy too. No special tools needed, just the basic stuff you'd find in your average dude's toolbox. I've got almost a 1000km on mine and I've had 0 problems whatsoever. Its a quality piece no doubt about it. I highly recommend it!