Yes, it is. I did mine in a '01 CC and it works just fine. I took out both seats (40-20-40), removed the arm console between them, removed the metal frame for the 20 "under arm console" seat, measured, and planned. I then cut the inside of the foam to as thin as possible, built a box, built a metal inner-frame, put the foam on the box, re-covered the foam with the upholstry, mounted the sub to he back of the box, and bolted everything back in place, using the stock threaded holes.
I'd take pictures, but it just looks like a regular middle seat with an arm console on top of it, and a sub coming out the back (I mounted the sub magnet-side-out for more air space).
All you have to do is imagine filling the center console with a box and you can get it done.
Im building a box right now. I have a 97 club cab. I dont know if mine would be able to fit in yours but mine is not quite what the other guy wrote. I removed the center console completely and built a box that goes with the contures of the seat. I have fiberglassed the top and I am going to carpet it today. THe sub is facing down and is right behind the two seats. I would be willing to sell you mine if your interested. I blew my amp a few months ago and I dont have any money to replace it.