Higher compression ration which can increase hp. I installed 49cc heads on my 305 instead of the 64cc and got a higher compression ration and a fair amount of hp gain.

No. In principal the compression on the leg joints will "slightly" decrease your height. However this will be compensated during the night, when you will actually gain height.

what does a compression program do? what does a compression program do?

Blasters are 2u strokes which means unlike the four stroke they only have the power and exhaust stroke. They dont need the intake stroke because the gas is already mixed in with the oil (yama-lube recommended) . Now u might notice a blaster doesent have a compression stroke. This is because the motors gain compression by not having a timing chain between the crank and the cam (because ther are no valves). This means there is no where for compression to escape thus giving u

Normally you will not lose any height when you lose weight. There is even a chance that as there is less compression on the spine and joints that there might be a bit of height gain.