I haven't used either of the subs you listed, so I can't give a recommendation on those, but I can possibly save you some grief with whatever you get next. You can install 3 amp blade fuses in the speaker leads. When an amplifier goes into clipping, whether it is because you are pushing it past it's capabilities or if the charging system/wiring aren't up to par, the uncontrolled signal gets "clipped" and the current rises rapidly. This doesn't add up to more volume, it just makes the fragile voicecoil winding glow red and fail. The fuses will stop this from happening.
We used to do a lot of hoopdies and these guys would show up with some sort of Colossus or thousand watt V-12 amp or whatever they could get "used" then add four new Kove Armageddons or Memphis LVS that were capable of thousands of watts each and show up every week with blown woofers. Even if they came in with something nice like a US Amps 2000X we could never get them to upgrade the alternator and use multiple batteries and caps. One of these amps would stall the engine driving down the road because it would take enough juice to even starve the ignition coil. Once we started putting these fuses in, we would get the cars in every week as before with no sound, all we had to do was change the fuses
