These might fit under the seat or anywhere else in a track/kick/sammi.

http://www.crutchfield.com/S-TnCIkmfYC0I/cgi-bin/ProdView.asp?g=51000&I=020SRV303

http://www.crutchfield.com/S-TnCIkmfYC0I/cgi-bin/ProdView.asp?g=51000&I=108BASSLIN

http://www.crutchfield.com/S-TnCIkmfYC0I/cgi-bin/ProdView.asp?g=51000&I=113WA62RC

They also carry the full line of bazooka tubes too.

Are these small subs any good  

Hey redboarder, post some pics of your install, I would really like to see how you put your subs in the tailgate. I have been thinking of doing the same thing myself.

www.Epinions.com gave the Infinity BassLink good reviews. I'm actually thinking about getting one of them myself. It's not the most powerful one ever, but for the price it's great quality. I've always liked Infinity audio stuff.

I had a basslink in my tracker, I liked it a lot. Not meant for SPL at all but AWESOme and i mean AWESOME sq.  Well worth the money.

how hard would it be to hook everything up to the stock stereo system??

Heres the job I did on my old tintop, never rattled once. sounded good too.

http://www.cardomain.com/member_pages/view_page.pl?page_id=283125

My current tracker has a standalone 10inch in a vertical box behind the back seat with my amp under a carpeted fake floor inthe back with ventilation provided via the hole between the back and bottom of the back seat. this provides ample storage for towstraps , juppercambles etc and provides some security in the softtop by keeping everything out of sight. so now that you all know don't rob me. lol  

for sunrunnerGT, i think it would be easier to buy a new head unit, amp and sub. trying to hook up a stock stereo to an amp and sub takes a bit of fiddling around. (from experience, i worked in a car audio install shop for 2 years)

with a new head unit, it makes the job all that more easier and keeps a lot of things simple. and it will also have a seperate sub controller in the menu if you choose a descent head unit.

and it only uses RCA jacks, so theres no cutting, stripping and soldering of wires.

if you would like to know more, i can try to explain and help you out as much as possible.

Cheers
Steve