The sealer we use is a part of the Diamont line, which we use,, DC30. Your local autobody supply store should be able to help you with maybe a generic sealer. Enamel is going to be pretty hard to blend in without a major line showing where you ended the paint coverage. A base/clear would be the way to go, even in lacquer as Dean suggested.

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95 SL500 Smoke Silver, Parchment 64K
07 E350 4matic Station Wagon White 34K
02 E320 4Matic Silver/grey 80K
05 F150 Silver 44K