My dad bought two left over 2006 FST Swtichbacks, both with 0 miles, brand new, and both 144 tracks. My dad likes how queit they are, the electric start, the push button reverse, etc., but hated it was small and more of a crossover midwest sled. We took his and stretched it to a 151 because the 144 and 151 tunnel were the same in 2006 so we did not have to put a tunnel extension on it, we put a 2 inch lug camoplast track on it because thats all you could go with a 2.52 pitch driver and we did not want to drop and roll it or change drivers. Did Holz A-Arms, Holz Spindles, SLP Can, Black Better Boards, and a ton of vents. We put SLP hot air elimination kit on the clutch side, Fire N Ice Side Panel Vents, SLP Console Vents, Fire N Ice Windshield Vents. The sled runs amazing, they make a stronger belt like the 115 belt for the FST that works very well, no problems at all. We have tried to get it lighter by stripping plastic but there just isnt a whole lot to throw away. Maybe a rear skid next year would help lose some more weight. But realistically it needs to come out of the front end, it is very nose heavy and understandably so. all in all this is a FUN sled, I took it up yesterday and went "FSTing". It went everywhere I pointed it, it pulls hard, spools up quick, climbs well, jumps okay, like I said all in all it is a very fun sled. It is faster than an 800, and from the specs the 2006 has the same engine as the 2009 FST Switchbacks and they are rated around 140 hp. The nice thing about FST's is you dont have altitude hp loss, so if it truly is 140ish then its 140ish everywhere. I will try to get some pictures of it and post them soon.