Don't dip anything with clear coat or risk losing the clear coat when peeling the dip off (yes, it happens). Additionally, the texture of dip attracts dust and grime very quickly. If you're going to pay someone to dip your car consider wrap instead. Alternatively, do it properly. Let your car shine.
Severe Damage Caused by Plastidip (w/pics) - Subaru Impreza WRX STI Forums: IWSTI.com
I'm still not sure I believe that one to be honest, if there was a problem, we'd be hearing a lot more about it, I'm thinking most likely it's not the factory paint job, even if he thinks it is.