You really can't go wrong with JL in my opinion. I hooked up a JL Audio CS110RG-W3v3 PowerWedge directly in the middle of my trunk against the back seats (ZCW is a nice bonus to access the amp w/o unmounting) and the gray carpet matches the trunk lining very closely, so depending on your install it can almost look stock. Since you want a double, I'd say go with CS210RG-W3v3-2 (but I can't vouch for how that one will fit).
The sub has a great balance of thump and SQ to me. Frequency doesn't go as low as I'd like, but I'm pretty sure that's a side effect of T-tapping the speaker-level sub wires as opposed to using the original signal. Also consider a sound deadening at the very least on the license plate and gas cap door, and maybe even on the trunk lid.
If money isn't an object, JL also makes a stealthbox enclosure for our cars.. but it's an ungodly 1200-1300 i think :-/ And if you prefer to match your own subs and enclosures, well that a whole other conversation!