The MTW and KS cans both work very well on the 50. Front or rear exit KS cans no real difference in power. The KS 1060 will make quite a bit more power than the cannister mufflers. If set per KS/DA instructions, the transition is awesome, and not real peaky if the correct prop is used. The pipe will change the powerband of the motor, and it will like to rev the rpms up to make the power, so if you go the tuned pipe route, use a prop like a 22x8 that will let it rev on up into the powerband (using a big prop to load up the motor with a tuned pipe and you are losing what the pipe is there for). The motor can take lots of rpms no prob. Just depends on what you are looking for I guess, the cans will not add a significant amount of power over the stock DA muffler, the pipe will, but does weigh a bit more than the cans. If it was me I would go with the tuned pipe, the 50cc motors love em.

PS, you may want to consider the full length BMB tuned pipe for your 50cc, I believe DA is carrying these now and supposed to make great power as well, and a little less finicky than the KS 1060 pipes.