Fluffy622,
They screw into the original parts. They just replace the one piece units. See attached photo's.
This is my MO5 Pro as I run now, Weighs in at 1350 gms, with battery and body and has 65gms of lead ballast. It has a ABR oil gear diff fitted using 500 000 weight oil. Other than that, all hopups are tamiya, except the outer motor heatsink, which is 3Racing. Our mini class weight limit is 1330gms ready to run. I do not mind taping the battery onto the mounts.
It has Ride 60D front tyres with Cross rears.
Later,
Calvin.