I just bought my son a 2004 TTR125LE and it appears to be stock except for a Pro-circuit slip-on pipe, not a full exhaust. Starts pretty good but still cold-natured. I see a Joker Jet Kit on Ebay that claims to fix this cold-starting issue and suggests a few other mods to increase HP and performance. Does anyone have experience with this kit and would you suggest it? Thanks.