Bottom line is the new M3 is amazingly good to drive. But the CSL is much sharper to drive. BMW made the car easier to live with every day, and they need that if they want to sell a 100k. According to the CSL owner, the current M3 feels similar to the E39 M5. The CSL is much more hardcore.
So basically just wait for the next CSL.
http://www.petrolhead.nl/2007/08/video_bmw_m3_vs_m3_csl.php