If the past 60 years has taught me anything it is that these big power ideas rarely, if ever, work and most never get finished and end up either scrap or passed on to the next guy with 'big ideas, no idea'.
Keep it simple, any more than 150 hp in the rear and your asking for trouble first drop of rain or even in the dry, I have spun my SS in the dry and that was with 50hp and BIG boots, now it's about 100hp I will need to take care.
Not that I am condemning all big V6, V8, turbo powered, none VW conversions as rubbish, not by a long way, just not the best idea for such a light car. I feel the power to weight ratio should result in a the ability to be able to drive a car without worrying about it leaving the road, despite the lack of power status..
But, each unto their own, god help 'em.*kicked my butt*