CSL is just an entirely different beast altogether. Standard M3 is built for comfort and usability. CSL is about all out performance and fun, that's it. Heck, the airbox on it is entirely different, someone retrofitted it to a standard M3 and it was ~£5k just for the airbox.
I really, really, wouldn't want a CSL as a daily, the tyres alone would be a nightmare in any conditions but perfect.