i sandblasted mine, then put on some 1500' paint. been on 2 summers with no flaking/peeling.
the 02 housing, did however, peel... as you can see somewhat. i used the aluminum finish first, and it turned out ugly as sin, almost chrome like!! not anywhere near aluminum. so i thought it would work as a good primer coat. but NO, it just flaked. but like i said, the manifold looks good yet.
ps... mines just the opposite of yours, 2g manifol, EVO 02