would you consider going a different route? i mean they are good subs but $1000-1300 for them is on the pointlessly expensive side.
your alternator should handle it but you'll need to do big 3 upgrade to be sure there aren't any bottlenecks in your wiring.
tbh i think you'd be much better off getting away from overpriced and annoying jl audio subs.
http://store.ficaraudio.com/ has tons of great options that even if they fail you can rebuild for a fraction of the price instead of needing to buy a whole new subwoofer as well as being top of the line quality and performance with tons of customization options.
i know being new to this you are thinking "jl is the best that's what i've been told" but this simply isn't true. jl has a terrible price:performance ratio so even with their sound quality upsides you could of just went with another brand and got the same end result for half the price.