Brewology

I was wondering maybe they could put your own music in smashgpsp, also it would be cool if we could play smashgpsp on the PC, which would be cool because we will have better possibilties for smashgpsp on the PC and with those ideas we could think of ways to put something like that on a psp you know...

That is what the ARENA EDITOR is for. As for the SmashGPSP on the PC, it probbably has been thought of, then scrapped. It is for the PSP.