1)You will likely have to have any crank besides the stock one machined to accept the ks parts.
2)Agree that unless top speed is a concern aftermarket cases are tough to come by. The polini speed would be my first choice though. Problem may be that aftermarket ks cases are difficult to find. Modifying the stock case is probably best.
3) There are a few great 38-43mm kits and pipes. I really like the 46mm pinasco acceleration-it would need case boring but minimal work to transfers.