you can knock the price of your whole setup down if you get rid of the JL 300/2 and find something that does the exact same thing for less than half the price as well
Theres tons of amps out there, just got to any online car audio site and just start looking. You also want to consider a alternator/ battery upgrade, the RE amp will tax the current electrical system pretty hard. If you plan on going with 4 woofers then you most definitly need those upgrades, get it done the first time around then you dont have to worry about it later on.
yeh im going to try and find a 200amp alt. or im giogn to get mine rebuilt. But im just going to run 2 woofers..I realized 4 is way in over my head in the work and money. So im ginog to probably 2 15" SX's ported