I bet it would be fast, but I'd prefer a good running twin. Something like a 1200cc (or smaller if forced induction) 130-140hp twin would be the ideal street bike motor imho. V4's sound a better than I4's but still have the smooth feel and tend to lack low end grunt. I really like the throbbing twins and their low end pull. Perhaps if it were a longish stroke, big bang v4....