Will this work?

2 Peavey PR15's daisy chained and 2 Peavey PR 15" subs daisy chained powered by a Crown XLS 602 amp. One side for subs and one side for tops with a active DBX x-over. The Crown 602 amp rated at 600/w@4ohms should work each cab getting 300w and their programed at 400w I know it's a little under programed but hey I not doing Woodstock just like to by more experienced sound folks thanks

[Nubus]

yes but the power isn't split in half like that

Actually it should be split like that if they are wired in parallel (ok there is a small difference from the extra wire but its minimal). The major problem from this setup is that he is underpowered and that is more likely to end up blowing his speakers than being a little overpowered. As long as you keep them amp from clipping you'll be fine