The only thing Buster needs to climb up is a Hypercharge or perhaps better Star Powers. Blockbuster increases his attack damage if teammates are close by. However, now you risk being wiped out in one wave of attacks, or giving up too much field in Brawl Ball. Kevlar Vest gives him a slight defensive boost and resistance to knock backs while his Super is active. Overall, the defensive boost is negligible and the Super doesn't last long enough for more value.