Money to spend - But what engine???

[lightning bug]

I think you should establish a budget. Find out what kind of driving you'll be doing, figure on an engine size and build a chassis to handle your engine output. IMHO, The chassis should be built 1st. Especially braking. Make the car safe, THEN build the engine. Also, do you want Fuel injection? Turbo? N/A? N20? Engines could get into $$$. So establish a budget for your engine. Also, keep in mind reliability. The biggest displacement isn't always the best. I'm not a big fan of the H20 VW conversion so I can't help, although I've seen it done before. If I were to go H20, I'd go Subaru or Rotary (my opinion).