My '00 e38 has small bubble blisters along the factory bead seals. I grounded it off only to see surface rust underneath. Had all four doors grounded to the metal and resealed and painted. Been using Krown for the past 10 years with no further issue. Mind you, this car only seen Summer weather only for the past 7 years. My daily driver truck has been sprayed for the last 7 years and no issues there. As long as there's oil residue on the surface of the panels there will be moisture dissipation and no rust so I don't mind the occasional drip. I actually ask my guy in Streetsville to drench it good so it has extra protection.
'05 GMC Sierra SLT Z71 CCSB 4x4
'02 Regal LS
'00 740i Sport