After a rather long "what would happen if I" tought process I went ahead and did it.
Due to the placement of the 2.3's not being the best acostical place to have my system, I took the "donut" driver, 6513, out in the hopes of increasing bass. I replaced them with the SDA 6511, the same as the other two SDA drivers in the array had . The reason I was told that Polk put the "donuts" in them was because they had too much midrange. Due to the driver having a weight on it it would produce less bass IMO.
After several hours of listening I am very pleased with the results. I don't think they are too strong in the mid's at all. As for the bass, it is hitting much harder and seems alot more linear. As for the increased mid's, well, I like the sound. IMO it sounds fuller and more spacial.
After all the 2.3 TL's don't have the "donuts".
I know that others have thoughy about doing this but I would like to hear if anyone has actually gone through with it and what there thoughts-reviews were after the swap was done.