The Kicker Comps sounded pretty good:
Kicker Comp 12
As for the Alpine E line, I've never heard them, but Alpine is a good brand so I'd imagine they are pretty good:
Alpine E 12
The Alpine I've heard is the R series, it was really tight and clean, I liked it a lot, I've considered switching to these:
Alpine R 12
What I current have are the Kicker CVR 12's. They hit really hard ( I have 2) its not the tighest bass, but it shakes everything in the area when its turned up. I'm a big fan of Kicker subs, so I'm biased.
Kicker CVR 12
But basically, you need to hear a few different things and see what sounds like what you want. Some are really sound but not tight, some are tight but not loud, some are a good mix. it all depends on what you're going for. Also you need to make sure you get the right box (go with sealed) and an amp that will power your sub(s). If you hear someone with what you think you want, just ask them what they have. Most people take it as a compliment.
Otherwise you have to go to an audio store and listen to the different ones, and as someone else mentioned, its a lot different sounding in your trunk. But, if its your only option, then its better than nothing.