Parapa is a great support in a 2v2. Thousand punches/kicks holds enemies still for a super from your team mate. My brother and I dominate with a Parapa/Sly combo.
The boombox is pretty silly though. The AP gain is so small that the only use I found for it is making enemies come after me.
They need to buff his boom box... my problem with him is people see me do a 90+ combo and people are like HOLY CRUD!!! RUN AWAY.. and well... I gotta chase them =\ if they buff his boom box it will motivate players to not want Parappa get isolated, because if I try to lure them with the free meter... they don't really care XD