Some of the wise folks on here probably know this already but could be good info for us Nubes.
This webpage shows the difference in the POLK BD 651 & 651S speakers physical profile.
http://www.lotustalk.com/forums/f133...s-db651-90072/

Apparently the DB651 speakers protrude out 3/4" further than the DB651s.

I really don't think that would be an issue for our boats though.