Here are some general tips to constructing a good subenclosure!
1) Only use MDF (Medium Density Fiberboard) It is much more dense and alot stronger than particleboard.

2) Prime and paint the bottoms of the enclosure to help prevent water damage in case of a leak in the trunk.

3) Use a router w/circle jig to cut the sub holes. This ensures a nice round hole and is much neater in apperance.

4) If the sub is to be surface mounted use a rabbet bit in the router.

5) Use 8-32 T-Nuts (From any hardware store) for mounting the subwoofer. Tis is much more secure since you are using a bolt instead of a woodscrew that strips if you tighten it too much, or have to remove it ONCE. This will also allow you to remove the screw with a manual screwdriver and not a screwgun (They always slip off the head and put a hole in the surround!!!)

6) All edges of the enclosure get wood glue (Liquid Nails works excelent too), screws (wood not drywall) every 4 - 6" and siliconed inside. This ensures a nice airtight seal.

7) The insides of the box should get sprayed with undercoating. This makes the inside surfaces uneven which can help eliminate standing waves that negatively affect the output.

8) Finally, all the terminal cup holes are cut with a hole saw and get a strip of 3M stripcaulk before screwing them down. Air can leak from here.
1991 Dodge D50 extended cab Pickup
This enclosue was built for the customers old ADS 10"s. There was a little angle that need to be put between the bottom and the back for it to sit properly in the cab.
1991 Ford Mustang Convertible
I tried this enclosure cause a local speaker seller told him it would fit "No Problem" in his Mustang. A 15" Kicker? Yeah Right, if you don't care about the proper volume for the speaker. If I had made this 1/32" taller it would not have fit, and it is within the speakers specs for airspace.
1993 Pontiac Firebird Trans Am
The customer wanted a plate for these 2 10" crossfire subs, and I for one am tired of seeing a plate in the back of the Camaro / Firebirds. The subs had white baskets (his accent color) so I painted the magnets red to match the car and mounted them "upside down" on the enclosure to give it the look you see here. He was estatic when he returned to see it, never expecting to have it look like this.
1995 Honda Civic
This enclosure was built because I needed all the trunk space I could get. The "clock" shape matches the spare tire well and the plate acts as a false floor. The 2 Kove Audio 10"s really sounded good too. Also I have always wanted a tool kit and I needed to mount the spare tire in the car so it worked out.