when using a hole saw to open up the baffles, I've been told to use a very slow turning speed of the hole saw to cut open the baffles. if you do it at a fast speed the baffle metal hardens and the hole saw dulls up very fast.
JV Sclafani Boca Raton, FL '13 M3W Metallic Orange Pearl 128CI Steered by Empire - Riding on Ohlins