48cc vs 66cc

If you are towing a trailer especially with some weight, go for the bigger engine.....it's made to make more torque and pull loads, not rev like the 48cc.

I think so - once you go through the 1-6 month cycle of tuning the 66cc

The main deal is the only real difference is the displacement - so basically all the stuff outside the engine is the same, regardless. Well as you might imagine - a 49cc exhaust, intake, carb, etc may be a bit of a compromise on a 66cc engine....but it's more than just upgrading that stuff while you replace everything that breaks. (Trust me, it doesn't sound like it - but this IS a good thing in the long run). But it does involve some labor of love....grinding and time and yes some money.......