I am getting an Acura TSX that will be used for primarily business purposes. I don't want to spend a lot of money (around $500) on speaker upgrades that will fit in the existing spots (I don't want to do any major cutting modding). Also, I would like to get by with the stock amp because I want to limit spending on a modest upgrade (car is just a beater/business car) and also taking up any valuable trunk/storage space. The car comes with 6.5" components up front, 6.5" full ranges in the rear doors and 6x9 (yes friggin 6x9's) subs in the rear deck. The amp (xovers built in) is rated 360 watts into 8 channels. What are some good, subtle, speaker/driver upgrades that I can make to make the system sound better (sounds pretty good stock BTW)? I don't need loud, boomy bass, I just want cleaner, quality sound and to tighten up the bass some. My listening tastes are mostly classic rock, some jazz, light R&B and ambient trance amongst other types. I have been looking at:
-CDT CL61's, CDT mids (which?) in the rear and TB 6x9 subs. (do I have enough amp to get the best out of the CDT's)
-Alpine Type R components up front, Type R coaxials in the back doors and Type R 6x9's in the rear deck.
-Diamond Audio 661's up front, M361I coaxials in the back doors and M391I 6x9's in the rear deck.
-Image Dynamics CXS Chameleons up front, CTX6's (or CX64 mid bass drivers without the tweeters) in the rear doors and dunno about the 6x9's. (maybe the Crystal Mobile CSx693's, TB W69-1042's, JBL Power P953's or the other two 6x9's listed above)

Here are the TB 6x9 subs that I have mentioned above (specs and price look great) :
http://www.nuera-acoustic.ca/product...s/W69-1042.jpg

I'm also considering Focals but aren't sure which models. The Diamonds seem to be the best bang for the buck from the specs/reviews that I have found but the Alpines could probably be found for much less and seem to be a great value to do a modest upgrade. The big problem is that I'm having a hard time finding mounting depths for these speakers. They're probably all over 2.5" and doesn't the TSX only have about 2"s in the doors and 3"'s in the rear deck to work with? Will spacers work OK with 2.5"+ deep speakers or will major modding need to be done that won't work cosmetically/functionally? Which of the above work best in shallow mounting depth applications and still sound good for the money? Again, I'm not looking to add separate subs or a new amp. Can I upgrade significantly by just upgrading the stock speakers or am I wasting my time and money relative to the improvement that I will get?

Thanks for any input,

Scott