Have you thought about turbocharging? The two stroke snowmobile racers have been successfully doing this for years. The turbo provides intake boost and exhaust system back pressure. The turbo can be used in conjunction with a tuned expansion chamber. The tuning can be tricky.
There's some VERY gnarly 2-stroke turbo race sleds out there. Over 500hp from a complete engine package that masses under 50kg, turbo and all other accessories in.
Brutally effective prime movers if your primary concern is power/weight.
I don't know what type carburetor you will use, but if it is a throttle-venturi design like on most motorcycles you will need to get the supercharger pressure in to the float chamber or the boost pressure will blow back through the jets; no fuel - no power.