i have the 2009 600 iq shift and love it. its all stock for this season, but with a few add ons over the summer this sled will scream crazy mad, right now it will keep up with my edge x for awhile, as far as comparing this to your 05,the 09 handling is better alot lighter this 600 iq will pull the skis right up and i weigh 180lbs at 6ft. tall. good luck i don't think you will be disappointed. if you can go with the 136" i only have the 121" wish i would've went longer>