I have 73 hours and 1200 miles on my 2012 450 XC-W. It's stock except for an FMF 4.1 and a Scotts under-bar stabilizer. I ride mostly technical single track, but I like to hit the MX track now and then too. I find that I hardly use 1st gear, track or trails, and at awkward times I am trying to get out of 3rd and into 4th - the gap there is just too big for the track. I've been thinking about changing the stock gearing (13/52) to a 13/50. I hope the smaller rear sprocket will give me a little use out of 1st gear, and allow me to stay in 3rd longer when I'm on the track. Any suggestions from anyone else who has made a change? Thanks!