what sort of fuel do you plan to run at 20 psi boost?! are you going to buy race gas at 10 $ a gallon? to run 20 psi on pump gas will take really low comp ratio/superior intercooling. you are asking what it will take to make a 350-400 hp honda really. thats a serious project that will usually cost big bucks. expect to spend a lot on the pistons alone. if you really think you want a 350hp + honda id say you best join a good forum and ask the experts there. just my opinion.