Hello miles_jamike,
Power Acoustik recommends a 1.25 CuFt sealed and 2.0 CuFt ported enclosure for the P1, P2 and P3 subs. The PSQ needs 1.25 sealed and 1.75 ported. In physical size, this translates into about 16X12X14 for sealed and about 30X42X15 ported.
You should try to stay pretty close to the recommended enclosure volume for best performance. A good volume calculator is located here on
the12V.com website. Just enter the proposed width, height, depth, and material thickness and click the "=" to get the CuFt.
If you are building (or having built) a custom enclosure for a specific location in your vehicle, all you need to do is stay very close to the volume recommended.
If you intend to purchase a generic enclosure, the Goldwood shown here at
Parts Express is an exact fit. Atrend also makes good generic enclosures, their model 12SAL in a sealed box with 1.20 CuFt and the 12LSV ported with 2.50 CuFt would be good choices.
Crutchfield has both generic and custom enclosures made by JL, MTX, QLogic, and Bass Slammer. Crutchfield has excellent support. They will respond promptly and positively to your phone or email inquires. If you have never ordered from them, you can use a "friend referral code", such as mine, which is: p7sdj-hrx8q-9800g, and on any order of $200 or more, you receive a $20 discount. And I get a $20 credit on a future order. Also, many orders qualify for free shipping.
Hope this helps.