Grant,
For the horsepower you're talking about, an Audi would be far more than adequate. Rumor has it that the 016 is quite reliable to 400 horsepower, and is just fine with more power provided you're not abusive to your equipment... not to mention that an Audi can be had for just a fraction of what you'll pay for a 930.
First gear in the 016 is a little on the short side but with a ring 'n pinion swap you'd be set - but that mod isn't real cheap either. Something to consider.
I'm not sure about the mounting setup, but I'd bet Kennedy has an adapter kit to fill your requirements.
As for the 930, you can't go wrong so long as you can be happy with a 4-speed.
Finally, there's a mountain of information here on the forum. Don't hesitate to use the 'Search' tool - it's a great feature which will uncover solutions to a lot of questions you may already have. A lot of topics have already been discussed at length and the answer is right there. At your fingertips.
Good luck with the build!
T.