The Muggy is not the same chassis as the 8t. A brake spacer should allow you to utilize the mechanial brakes. If you use a single high torque servo for steering, you have a built in servo location for brakes - just need to bend some linkage to allow it to pull the brake levers. :)

do you think the finned version of that motor would fit in, or does it have to be a smooth can? also, do you have the dust cover on the back of it? because i was thinking if i got one i would probably buy the clamp for it just to be safe

The finned version will fit, I use finned 1515 in mine. That picture does show the dust cover. What clamp are you talking about? If you are talking the rc-monster heatsink clamp; it won't fit. It only works on 36mm motors, Neus are 39mm smooth or 44mm finned.

oh right. because i was originally gonna get the Tekno-rc edition Neu 1515/1y which has the latest design to stop the endbell from popping out. but i think i've since decided to go with a 1521/1.5D for the extra power but it doesnt have the latest endbell design so i wanted to get the rc-monster clamp to make sure it all stayed together

I think all of the new Neus have screws in the endbell, they won't come off. Even the older ones have had little to no problems with endbells popping off.