brahma, shiva, or tempest?

i got to hear another brahma today at school and was instantly sold. i also got to hear 2 tempests as well. i am looking for ideas what kind of sub setup i should use for spl and sq in a bmw 318. i havent measured the trunk because the car is sitting in long island and have never done an install in one so i have no idea what room i am working with though i am will to take out the back seats.    i am hoping for high spl so i would like to build a wall. i have 2-3 grand allocated to subs and amps so for what i am trying accomplish, funds are a bit tight. did i also mention, this will be for a convertible, which thank god i have never installed in before.    my other problem is that i cant decide on amps. i was looking at a couple of cadence, hifonics, and jbl amps