Here is what another person had to say about the W6 and the W7 and db's.
With my experiences with the W6's, they gain considerable output when ported and do not loose all that much sound quality. Depending on your own personal preference, they may sound better to you. In my car, my 13W7 hit a 142.6 Termalb ported off a JL 1000. My 2 12" W6v2's hit a 142.1 sealed off a JL 1000. One W6 in a ported box hit I think a 140-141 I can't quite remember.
My recomendation. Port them. Do not spend the money on a 13W7 unless you want a single sub setup or for some specific reason. I think you will like the way they sound ported. As for winisd. Just forget about trying to use it and concentrate on building your box. It does not really help all that much in my mind. The only thing it helps is somewhat with the port length, but since it does not take in to account port extension and volume diffences it takes forever to get your tuning right. How big is your trunk. I would think it should be plenty big. I am working on a box for a ford zx2 and we are putting 3 W6's in there. If you have about 2 cubes per sub you will be fine. For the port tuning if you listen to a varity of music and are not over concerned about SPL, just keep it in the low 30's and it will sound great. Go to JL's website and look at the tutorial section. It will help you out on building your box and there is a equation there to find port length. Take some measurements of you trunk and post them so we can see if there is enough room.
I am gonna be running my JL 12w6v2 ported also at 1.5 cu ft tuned to 32hz. I hope i get over 140 dbs with just one ported.
Yeah James hit 146.7 with his Avalanche 15 sealed at 2.5 cu ft. I have a Avalanche 15 also but need a box for it which i will get. James also had the 12w6v2 ported before. This guy says he hit 141 db with 1 ported which is nice.
