Is the exhaust full or a slip on? The PC is worth it but you need an exhaust and filter to get the most benefit. Don't think of it as HP gain only. Your motor makes plenty stock if it's tuned well, ie, fresh plugs, etc. The engine is an air pump. Within reason you goal is to move air through that pump (intake/exhaust) as efficiently as possible, Hence the re-map,PC, pipe, etc. It's still a compromise though. If you're looking for mileage, might try a moped. But mapped and efficient, you should still get 40 mpg roughly depends on your riding style.