The problem with the cummins stuff is that they were designed to run a lot of boost. Most gas v8 motors aren't going to run that high. You could run two of them, but it's far from ideal.

The cost of the turbo itself is probably only 25% of your total bill to do something like this.

10.8 is pushing it, but with race has or alcohol you could do it. Not going to work very well with pump gas though.

What are your power goals? Remember it's more then just a turbo to make big power. You'll need a Trans, axle, chassis, and fuel system to keep up.