So after I put the pcv on my 08 800 Dragon 155, I thought that was the best mod. (Sled is running killer). I just installed a challenger extreme 163 with skid extension, Avid anti ratchet drivers, anti stab wheels. Wow what a huge change. This sled rips. climbs and side hills thru the trees way better than with the oem track. Best two mods IMO.