1. The engine needs to be reliable and able to be driven on a daily basis. There’s no telling how long or how many issues this engine will have as a result of the extra stress involved with making that kind of power. Only time will tell, but with that kind of power I’d assume a full rebuild will be in order somewhere b/t 50-75,000 miles. The cost to rebuild that engine without all of the Gpower goodies is well over $15,000 if not more. The engine itself costs $25k to replace in stock form.

2. An 800hp car would cost $10,000 a year to insure. Not many people are willing to pay that king of money for car insurance. Ins. companies would view that car as a death trap.

3. Driving an 800hp car on the street takes brains and a lot of restraint. It would be very easy to get yourself in trouble during a light rain or when cold out, those types of situations that we usually take for granted in our daily drivers. Even my Dinan 135 is scary to drive, especially on a day like today when there’s 3-4 inches of snow on the ground. I can’t imagine driving this car on a day like today. You wouldn’t go anywhere.

4. The cost to put an 800hp engine in a car is much more expensive than a 500hp engine. I would bet it would add $15-20k onto the price of the car, making it much less affordable. Not that it’s “affordable” to begin with, but another $15-20k bumps the car up to the next level and would turn off a lot of buyers. Especially when the M5 is already more expensive than the competition.

There are more, but that’s all I have time for.