Anything from a reputable name brand should work fine.
Alpine, Pioneer, Sony, Kenwood, and JBL all make good sub amps.
I would put at least 100W RMS (~250W peak) into each speaker. If you can get 150-300W RMS (~375W-700W peak) going to each, that would be optimal.
If you can find a 2-channel sub amp, that would serve your needs best, but you can also run both drivers off a single-channel sub amp too.
Just remember that if the speakers are 4 ohms, connecting them in series will yield an effective impedance of 8 ohms, and connecting them in parallel will yield an effective impedance of 2 ohms. Finding an amp at 2x100-200W RMS (at 4 ohms) or 1x300-400W RMS (at 4 ohms) would be optimal (not too expensive, but also more than powerful enough).
Make sure to grab a 1 farad (or more) capacitor as well to keep your tail lights from dimming when the bass hits.
I'm on a page about incorrect corrections, and spent the better part of like two hours trying to get someone to understand that -5^2 = -25, not 25, and then that post had comments get reposted because that group is self sustaining, and that person was in turn trying to explain what I just explained to them. And I'm taking that as a victory
I will be AFK for a couple of days you guys hold down the fort while I am gone. I will be checking in on my phone but that will severly limit me. Be back saturday!