Hi, I am building a tube frame race special for autox and hillclimbs and maybe street use if I can get it legal. I plan to use a donor rear wheel drive car like a miata or e30 for the suspension components and pickup points, steering rack, etc. I plan to use a honda engine and transmission mounted towards the rear for the powerplant because of the power to weight advantage.

I come from the subaru world though and don't know much about the honda engine series. This is a budget build though so I'm looking for the best bang for the buck. I plan to turbo the engine, not sure if I want to build the bottom end yet. If you could suggest an engine that takes well to boost in stock form (looking for somewhere around 300 whp with a decent torque curve too, its ok if it's a little peaky though) as well as a good engine to build and what I might be looking at for power. Please recommend a transmission as well. My thoughts on engines so far have been the b series and the k series, not sure which specific one though and k20s seem a little pricey.
Thanks