I'd agree with you and go for the performance. 8" of difference may enable you to miss a rock or two, but a 1' wave or a wake would remove that advantage quite fast, and you'd hit. You're certainly going to pick the same anchorages in any case. In the Bahamas there isn't a lot of tide. Being 400 pounds lighter, along with all the other go-fast gear, will definitely make a difference in how the boat reacts, and your the deeper, probably narrower keel will help improve upwind performance as well.
Of course, if you REALLY wanted to improve performance, you could have them get you a lead keel. THAT would enable you to reduce the wetted surface too, and not have to worry about rust so much.
Great, so we are two people with the same opinion... I double check for lead keel but not available from Jeanneau.
My friend who help me in this purchase as a F1 boat with Kevlar stuff but for me, the deck saloon aspect was more important then .05 knots!!! So I'm not a performance super freak but I like to have the best sailing capabilities boat with less inconvenient as possible.
Like I said, 8" is not much because I will start to freak when the depth indicator will shown 10 ft or less whatever if I have a 6'7" or 7'3" draft!!!!!
My very first choice was the shoal keel but too much sacrifices for that.