Some new ideas for my Slant

If power is what you're after, might as well build a V8 and get it over with. But, as you've already stated, you're not looking for lots of power, just improved power and throttle response. You can easily get the improved power you're looking for with a n/a slant, although it seems like the folks over at slantsix.org are the only people that can tell you how any more.

And since you're looking for throttle response, I don't consider 'gutless below 3k rpm' decent throttle response.