so i need a track for my edge x 600 and i figured i might as well spend the extra 100-200 dollars and extend the track from a 121 to a 136. i also blew out the rear shock at the end of the season. so should i replace the stock fox shock with somthing different? if so what should i put in it. i dont really want to replace all the shocks. the fronts are fine. also where do you guys reccomend i get the extension from. ive seen some pretty good package deals.