I found SRP to be great for the placcy rear window, not tried it on bodywork!
Truth to tell, since I've become a convert to JML waterless wash, I've not polished either car for a couple of months, cos they shine like shiny things in Shinyland after they're done. Never thought I'd recommend such a thing, but it really works.
.I used to be a Mer fan, but since I discovered Showroom Shine I have never looked back.