the only buggy thing about it is when you transform, it goes back to the original model,
example, you start as normal vegeta and type "model brolly" in the console, vegeta is now brolly with vegetas original sounds, when you transform the transformation effects go as normal but at the end of it the model changes to ssj vegeta. when this happens simply bring down the console and type model brolly again or even ssj brolly if you have that too.
as i said before it doesnt work if the server has "lock player models" ticked in the game options but its perfect if you want to face off against some bots. i use this method with picollo, and have binded { and } to picollo with and without cape so after i assend / decend i just hit { or } to get my desired model up. to do this open the console and type
bind "{" "model cape"
*cape being my model name.
sounds are a different story, i have no idea how to change sound directories within the game so you cant have both the original characters sounds for the normal model and your custom sounds for your custom model, you will need to pick what sounds you will want to use, unless someone knows how to do this which i hope they do caus i would like to know how to do it too.