I agree. There is a reason the engine is rated at the current horsepower with the accompanying warranty.
I spent most of my time designing aircraft drive systems and subsequent modifications. The chain of events that occurs from changing one little thing can drive you crazy. Don't you think that if the engineers could give you 550 HP right out of the box they would? Don't beleive the crap about management or oil companies 'not wanting to let us have that 200 Mpg 500 HP engine.'
I have considered supercharging the engine, but only considered it. Once you go down that road, be prepared for all sorts of quirky behaviour, let along component failures.
My favorite was the time I went off-roading in a 1970 Mustang that I had reworked. One of the steering components had to be lowered just a half inch to provide clearance for the exhaust headers. The part used looked like it came off a battleship, so one would think all was well.
However, a thing called metal fatigue visited the attach point for the added part. About three years after the 'fix', the mount point failed and I suddenly had no steering. Lucky for me the car made a right turn, avoiding the oncoming traffic. I can't blame the engineer that designed the car, he had no idea that the part would be subjected to the type of stress applied.
The same is true for the H2. It looks beefy but I would be wary of adding parts that increase loads, especially on the drivetrain. The CATIA system they use for designing this stuff, allows them to simulate loads and shave many pounds off the vehicle. That's great for performance and gas mileage, but bad for adding extras that weren't planned in advance.
If you want to see a spectacular failure of one of my designs, check this out:
http://www.dfrc.nasa.gov/gallery/pho.../ECN-31808.jpg