Need advice for a 2013 silverado extended cab
 

Hello, I am new to this forum so please excuse me if there has already been a post about my situation. I have been wanting to install subwoofers in my truck for quite sometime. I have been looking into putting 2 8"s outfiring, soundoff audio makes a box for my 2013 silverado extended cab and the specs for it are: Dual 8" 1.2 cu.ft mono chamber after woofer and port displacement, Mounting depth is about 5.5"-6". Now I have been doing a lot research in which subwoofer I want, It's between the psi-8 HP or the DD audio 1508, they both are really close to specs as far as airspace goes. The psi is rated at 0.4-1.0 cu.ft (optimal is 0.75 cu.ft ) Mounting depth is 5.5". The dd audio 1508 is rated at 0.75-1.25 cu.ft not sure on optimal for this sub the website does not say, Mounting depth is also 5.5". Now my question is would any of these subs work well in the ported enclosure soundoff makes and if they do work will they be efficient without problems ? Or should I not even bother with 8"s in the ported box and just do something sealed.

Sorry for the long post but hopefully some of you can help me out. Thank you. Any kind of advice and opinions I appreciate.