Get the high compression head, performance clutch pads, a copper gasket, a high performance carb, a good exhaust with a chamber, the performance cdi/coil, ngk spark plug, 35t rear sprocket with the hub adapter and 1”adapter for the sprocket adapter. It’s really good set up. It goes 45 maybe faster down hill and like 38-40 up a graded hill. Not good for climbing tho. You want to keep a decent speed with this gearing but it rips. If you want to climb a 37t is a good medium for my set up. A 40 would be real torquey. But super satisfied with this set up. It’s plenty fast and reliable. I recomend all these mods. I don’t have a ported cylinder or the ported piston or a reed valve but that may happen soon but for now this is great