FWIW, and it's just my experience (could be user error), CSL topped by C2V3 was among the poorest coatings I've tried w/ respect to self cleaning. I think it actually started doing better a month or 2 in, maybe when the C2V3 wore off?
I did 2 coats of CSL which some say was a mistake and really enjoyed working with CSL, it lent a nice, rich look to the red paint I used it on but it did leave some (easily removed) water spots after each rain. I hear EXO addresses that shortcoming, however.
About 8 months and 15k miles after applying the CSL, I decon'd the vehicle and put CanCoat on top which really improved the performance in the areas I found lacking while maintaining the underlying richness of the CSL. Who knew?
Someday I wanna give the CSL/EXO combo a try again as I really liked the CSL during and immediately after application. Gtechniq seems like a really solid company and I also just plain like the name 'Crystal Serum Light' and the packaging too. Kinda goofy attributes to consider but, I dunno, that kinda stuff appeals to me as well.