I've never heard of "4T". Looks like they are roughly 4.5" speakers.
If it were me, I'd return the Future Shock purchase, and buy from a store with higher quality gear. Then again, I hate Future Shock.
Hmm...a quick Google suggests that Crutchfield sells a Pioneer coaxial that will fit in those holes:
http://www.crutchfield.com/S-qw3BL0Y...x?i=130TSG1042
While that would probably improve your sound, I'd seriously consider trying to install at least a 5 or 5.5 inch driver in there, if you have the time/patience/werewithal.
You'll get very little power/bass out of a 4" driver, by almost anyone's standards. A driver of at least 5" will give you a little more bass.
I know sometimes the work gets annoying, but in the end, it's usually really worth it. At least for me, it was...
Oh, wait, I mean IS. I still have more work to do on my 2000 Camry. (pics in another post)
Philippe