Personally,
I think the requirements of having a good setup is
#1. The amp. You cant have a fast reacting, loud system without having a good amp. ANd the amp is usually a slight bit more expensive no matter what you get, and it should be, because it is the heart of the sound. So get a nice one. And Im not sayin do a 5 channel all-in-one amp to save a couple bucks. Each AMP in your ride should have a purpose. And if that purpose is to add a sub, you should get a Mono, or a 2 channel amp specifically to pump watts, because if youre gonna get a nice top-of-the-line sub, most of them with thier huge magnets, and large rubber surrounds require some juice to play in the sweet spot.
And its better made usually, in the upper class, so it wont overheat and shut down in 110 degree summer days, in your trunk, when your rolling the lakes, and your favorite song is on, and youre kickin back with your friends ala mind numbing Pantera song number 6, you don't want that thing to shut down at volume 24. lol.
#2. The box. The box should be one of an enclosure to meet your needs.
If you want that fast, quick, bass, you should go sealed. If you want the deep boom and play some frequencies a lil louder, go ported. But you said you like rock, music, go sealed.
#3. The sub is last. Truthfully, you can buy a cheap arse sub and still get great results. But if you dont have a nice AMP, and back that up with a well made box, thats suited to your music, Its not gonna react as quick, and be as loud.
Screw the 10"...you need two 10's to give you that kick. You need one 12" to give you the same effect IMO.
Diss me on this list I dont care, but really, If you want a good system, this is the order of most importance to me anyway. Because if you buy a sweet sub, the amp will be the weakest link, but never vise versa. Cause like Im sayin, you can have a crap sub, in a nice sealed box, and it will still sound very decent.
my 2 cents. Just make sure you get a AMP that is in the OHM specification you need to match the sub to play max at 4 ohms, or max at 2 ohms. Its your choice. PPI's usually play max at 4 ohms bridged.
I believe those mono JL audio amps play max at 2 ohms bridged.
a couple great subs that I personally like for example are:
http://cgi.ebay.com/ALPINE-SWR-1242...ryZ18803QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
^ dont buy that one, its used,....just an example, Ebay usually has 12"'s usually for 144.00 shipped reconditioned.
http://cgi.ebay.com/ebaymotors/Kick...017QQitemZ270185879781QQrdZ1QQsspagenameZWDVW
http://cgi.ebay.com/BRAND-NEW-2007-...ryZ18803QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
^^This one is an aluminum cone^^, the titanium cone one is a lil more expensive but its worth it.
http://cgi.ebay.com/NEW-JL-AUDIO-12...ryZ18803QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
If I had to choose, I'd say the L7, or alpine type-r,