Need some advice

ok let me say first off sorry for the long post but here we go. I have a 92 Dodge stealth RT, awesome car very very small trunk. i have been doing audio in my vehicles for about 8 years and never got into anything very heavy just cheap stuff from here and there. i kinda got stuck on sony xplode stuff. ok please no flaming about what i use. Right now theres a sony 1100 watt max 10" explode in my trunk hooked up to a 1000 watt max sony 2 channel amp thats bridged to the one sub. it provides ALMOST enough bass but i want to add another sub. i wanted to use two bass tubes just for the fact that they would be easy for me to mount and not have to remove should i need to access the spare tire. (nothing like setting you sub on the ground in the pooring rain to get your spare tire!) anyways i cant find any unloaded bass tubes (so i can add my own subs) and have read horriable reviews for the bass tube design. now my question is can i do anything to make the bass tube sound better, or with what i run now will i notce a differance in sound quality. (Btw the sub in the car now is in a sealed truck wedge as there is not much room and i had the truck box around) i want decent sound quality and be able to feel the bass in the car. i can feel it now just not enough. any advice would be greatly apprecieated! if you want to know anything please just ask.

ok sorry i forgot about my other option. i can use two real 10" subs but they have to have a mounting deapth of less then 5 7/16th on an inch as that is all the space they give you in the box you can see a pic of it here http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=009&category=38647&_trkparms=algo%3DMESSL%26its%3D%26itu%3DSS%252BSI% 26otn%3D1%26po%3DOp1&viewitem=&item=190195135649&_trksid=p3984.m106 . any suggestions on some inexpencive subs that will fit?