i'm going to get this JL Audio CP108LG-W3v3 FlatWedge™ slot-ported enclosure with one 8" W3v3 subwoofer at Crutchfield.com
powered by a jl 700/5. should have it installed either next week or the week after. the sub and box are about 18"x12"x6", so should still leave me some trunk room in my 2 door.
i was debating the basslink or something like it, but decided on a 5 channel amp to give more umph to the mids and highs and provide the power for the sub.
i'm going unpowered sub enclosure because that way a)if it gets stolen, it's not as big a loss, b) makes it cheaper/easier to replace/upgrade, and c) lighter and easier to move if i want to take it out if i'm leaving the car parked somewhere like the airport.