SuperTed,
Haven't paddled the standard FG version of the Sport, only the Ultra, which is extremely light at 23-24 lbs. I believe the FG would come in somewhere around 32 lbs. as the V10 does. That still makes it lighter than the 39 lbs. of the FG XT. For comparison's sake, my Huki S1-R comes in at about 27, fully opted (6" hatch, adj. footwells, etc.) I did paddle the carbon XT twice (picked up a beautiful one for a friend), and would definitely go this route over the standard if this was the boat you wanted and could afford the extra $$. It just feels livelier in the water. Using the 4" rudder vs. the standard 8" would give you a tick of speed as long as you weren't venturing into anything beyond its (and your) capabilities. I have both the 4" and 8" rudders for my Huki and it pays off on flatter water.
"Nice? It's the only thing," said the Water Rat, solemnly, as he leaned forward for his stroke. "Believe me, my young friend, there is nothing -- absolutely nothing -- half so much worth doing as simply messing about in boats."
'The Wind in the Willows'~Kenneth Grahame