Papermaker85 5,000+ posts
Banned
If you gaied with 2 12s it was user error.I ran 3 12's and recently switched it up... sold 1 and now run 2 in a much larger box. I got a notion then some advice from here and did it... this is how 2 turned out and I seem to have gained overall and make more efficient use of my power. Get a load of this... [http://i.imgur.com/BgrwbZT.jpg] ... in a Blazer not a Corolla. Think about it... you still need room to mount your equipment.
In a trunk install as long as you have 4"s from the rear its fine.
Ive tested more than a few configurations. The box would be 6 cubes with 90in^3 of port area and it will be louder and have a flatter response. Sure you could get a larger peak around tuning with a larger box and two 12s but your going to loose ouput below and above tuning..
Typically id say go for a 18 in that sized trunk but 3 12s would work good.
Show this weekend. Shoukd beable to hit a 146.5 with 1 15 in just a basic install..