we just got the 2010 versions of that mower. 34hp 48in. i am gonna get or make a weight kit though, i am a bit heavy for the hills i have to use this on. the cables on the newer ones do make it go faster i think, or at least they can be adjusted that way(mine are fast already and have plenty of adjustment left to go either way.)
if you have not had the update for the cables, this may be able to have done.