Donny,
I'm familiar with that page/mod/product. The chip shouldn't hurt anything. The only problem you might get into is emission standards of California. Just swap back to stock when you get it tested, then swap back to modified mode after you pass. Since you are getting the full "brain box" and it is tuned by AMG the price is not out of line. Renntech chargest that much for a damn Eprom! To change the brain box you will need a special tool. (I forget what part # number but I will look it up if you want) It basically aides in the seating/alignment of the computer module. A normal "chip" should run about $400-$500 but for a complete computer upgrade $850 is reasonable enough. I would assume some kind of warranty applies... Also since it is AMG you would think the price would be doubled. If the box is tuned by AMG then you know it shouldnt cause any problems. They basically work by enriching the fuel/air mix and advincing the ignition timing. My only criticism is that they might not offer the most aggressive program out there. Given California emission laws that might be a good thing... When you do get it let me know how it works for you...thanks.

Enjoy....Lee