I want to start building the box for my 15" FI BL soon. I originally planned on 3.5ft @32. The external width is going to be 37.25 wide, with the sub up and port back. I planned on 2 4" precision ports to save some space. I was wanting to keep the depth of the box as low as possible around like 17" or so. The problem is with the ports they would be fairly close to the back wall (not mounting them externally). 3.5 @32 calls for 17" of port length. So that ain't gonna work, especially since I can't find any pvc elbows locally that will work. Then I was thinking I could go with 4ft @34 with 12.75 long ports. Thinking that would be far enough from the back for clearance. This is what I am leaning towards doing. Other options would be ports to the side or slot port. Thoughts?