Lots of controversy/opinion diversity on this question. IMHO, if you have a clean, just blasted surface, you should not use etching primer, rather, you should use epoxy followed by a 2K primer when you are all done and ready to finish up.
There are many threads on the topic posted at hotrodders.com and the guy I trust the most, deadbodyman, despises self etch primer as a crutch and not a good one at that.
