>>Don't most subs come waterproofed. Kinda defeats the purpose if they aren't.

This is why there has been so much recent interest in sealed subs. They fix a number of waterproofing issues in addition to the arguably "more musical" sound.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8