Pair of inexpensive 15's in a wall or even just a 13 cube box in place of the back seat. Fire them up with both subs together and the port on the side of them.....firing up also. 250 square inch vent 13" long, inititally. It's pretty hard not to score a 150 with a pair of 15's like that on say 1000-1500w. SoundStream has a cheap ayss 2000w amp that is no joke for $391.00. 0ga power and ground, stock head unit with a Line Level Converter and some wood, glue, brad nails and a steady hand and you've got yourself a sub-$1000 system that should definitely hit 1fiddy. And still do what you are actually after.........get loud and low.
On the side note, atleast at 15 you were not on roughly 2-3 hits of acid daily. Be glad you know that you have a small problem and just cold-turkey that b!tch. I was on acid for basically 6 years. And yes,.................it sticks with you....it sucks. Get rid of that nasty ayss dip too, chicks can't dig that sh!t if they have teeth of their own.