for those guys here who have built the pro kits.....what measurement of tools do they require? metric or imperial? also....a good recommendation on an engine (not for racing). looking for something with good bottom end and mid range power. budget is $180-$220. also what pipe to go with it...i see a nice JP-2 on ebay for a good price. Should i look for an engine that has an overall good powerband and then get a tuned pipe to enhance the top or bottom end?