I have an 06 and here are some things that I've done or at least going to do ...
The 06 model is notorious for the shifter bezel module(TCM) to go bad and therefore gives off wrong torque management data and you feel the backlash from the accelator ... there are two fixes to that ... interestingly enough the SRT8 has the same transmission and some of them have replaced the starter and the problem seems to go away while some of them have had to replace the top assemble of the shifter bezel that is quite costly
the clunk going over bumps in my case it was my rear track bar and after replacing that it went away because after each time i went over a bump the car shaked side to side making a clunk noice
also what these guys have mentioned about the sway bars
that should be a good starting point
The top bezel can also be cleaned ... clean the contacts and see if that helps
here's a thread that'll be useful let us know if u need more help