The 93 is a freaking awesome board! I love that it has got all that speed yet remains so composed when taken out in the gnarly shit. I sail it almost exclusively with a 7.0 Naish Grand Prix. They are a stunning match. I love sailing overpowered out at our local cross-on spot. Take all that top end speed and then go searching for the biggest ramps out there. There will be no one who is boosting higher! Killer board!
The fin is critical. I've tried a heap. An upright fin lowers the angle of attack of the board and also provides and bit more upwind drive. Perfect for flat water speed. A swept freeride style fin has a tad slower top end but lifts to nose a touch and provides heaps more control if its gnarly. I definitely find them the faster way to go in the rough.
The biggest fin i run is a 36 Techtonics Maui. This is great for lighter winds and upwind missions but gets to be a bit of a handful when it starts to pick up (i weigh 67kgs). This would be a stunner for speed in a smaller size.
I've got a MFC K-One FR 34, which is beautiful fin (much better than their Liquid Pro imho) but is still a little big for me in the heavy stuff (they don't do a 32 yet, though they should!). The MFC SL2 is a sweet fin too. I've sailed the futura93 with the 32. It felt a bit small for all round sailing with my 7.0. If i was to buy one of these i'd go for the 34.
My favorite fin, however, has got to be the WhiteWater Ride 32. It is really fast (my mate clocked 32knots on one the first time he sailed one) and has amazing control when overpowered in big seas. Excellent grip. Super predictable. Really easy to pull back in if you push it too far. It is bloody hard to get hold of these things though.
Then for super flat water and stupid amounts of wind i've got a 28cm elliptical blade. This fin opens up the top end wind range by a good 5 knots over the top of a 32 but requires more skill to sail and is definitely slower if i'm not massively overpowered. I don't use this fin that much.
A crap fin sucks. There is nothing worst than a fin unpredictably spinning out for no good reason. Life is too short to sail crap fins.