One of the better engines to use is the OS 18CV or 18TZ series. They are bolt right in with no mods to chassis or engine mounts. Very easy to break in and tune and good on fuel consumption. You could shoehorn a .21 into the car but will have to do some mods and have plenty of clutch shoes and gears that you will tear up with the extra power. You could also just go with any of the new .12 engines are modded that have tons of power now (some are just as fast as some .21s). Pipes are like always, just have to find the right one to fit the engine that you choose. Hope this info helps.