Hello forum! I'm fairly new to car audio and even newer to this forum in particular, but there appears to be tons of great information here from numerous people with years of car audio expertise so I figured I'd start here for help. I am wanting to upgrade/modify my current subwoofer set up to create a cleaner appearance in my vehicle and perhaps increase the "loudness" factor as well. I currently have 2 RE audio SR 10's running at 2ohm's at roughly 1200 watts rms in my 96 gmc sierra. The box has been placed where my center console used to be and I really enjoy it there as it allows me to keep most of my backseat. What I'd like to do is replace the 2 10's with a single 12 or 15 if it will fit while keeping the box in the same location. For the box itself I'd like to fabricate a custom enclosure out of fiberglass. I have a friend who has worked with fiberglass and assured me that creating the box itself will be time consuming but for the most part fairly simple with a bit of help. What I'd like to know is if anyone has any suggestions on what size and kind of subwoofer to get using the same amplifier (1200 watts at 2 ohms) and a budget of around 150-350 dollars. The second question is more of a fabrication question for the box in general. I'd like to keep the box ported and in the same place it's currently at. I have made a small diagram displaying the dimensions available in the truck and also attached a picture of the 2 subwoofers currently in the vehicle. The smaller 6" line on the diagram is additional room if needed for length. The 15" is basically in the same boat except it's for width up front where I'd like the speaker to be placed. If anyone has any suggestions on speaker placement or box design let me know! Thanks! Sketch of the truck interior with dimensions http://i1228.photobucket.com/albums/ee448/smjharley/Sketchoftruckinterior.jpg Picture of the current subwoofers and box http://i1228.photobucket.com/albums/ee448/smjharley/2011-10-22_14-55-14_319.jpg