ported vs sealed l7 enclosure

I am trying to design an enclosure/amp rack for my truck. I have 2 12" L7s DVC 4 Ohms. I'd like to try building a ported enclosure. Kicker recommends a 3.25 cu ft with a 3" x 13.25" x 14.5" port. If possible, I'd like to use a round port so that I can use simple PVC pipe and cut a hole for it as opposed to trying to build a square port out of mdf. Can you do this? Using WinISD I designed a box with a 3.5" round port that is 2" long. That seems kind of weird to me, anyone have any advice or recommendations? Thanks.

That box would sound like a turd, I guess thats why people complain about the L7's SQ.   Will both sub's be in the same enclosure? If so, the smoothest I could get that horrendous sub to graph with that 3.25 cu.ft box size was porting to a frequency around 15hz. Are you going for all out spl, or a street set up that must actually play music?2003 Chevy Avalanche,Eclipse CD7000,Morel Elate 5,Adire Extremis,Alpine PDX-4.150, 15" TC-3000, 2 Alpine PDX-1.1000, 470Amp HO Alt.

No they are going to be in separate boxes. What makes you say they will sound like doodie in that box? Should I be looking for a flatter curve? I know people can only hear down to about 20Hz so is it worth tuning for lower frequencies? I also have been playing around with larger box sizes ~5 cu ft a piece, the curves look a lot different, is it worth exploring this larger size? Thanks for the help.

L7s do not have any outstanding sound quality problems. They are some of the more capable but miss understood subs to ever enter the car audio scene. I have Three questions for you. What is the production year of your subs, what amp will be powering them, and what type and year of truck do you have? The square port can be converted to a round design easily enough. The frequency curve that you show dose not look desirable, but I will not comment any farther until I know the rest of the variables. You can not make an absolute judgment on a box design based on frequency response alone, with out knowing the vehicle, amp, and the remaining specs for the sub.   

They are 2004 12L7s.  I am building a box in the back of an extended cab ram '01 ( i took out the back seat and am building the back to have 2 sub boxes, an amp rack, and a source for 12V+ in the back.  I have 2 KAC-x811Ds (1 to each sub).  Nice pic.