OK lets rank what is the best mod free or otherwise that you have put on your bike. 1= The best thing you have done 10= Either a waste of time or money. 1. uncork the Exhuast 2.the right jetting. for me (larryco or JD both where the same for me) 2. Power now 3. grey wire 4. YZ Tanks and seat 5. Race Tech Valves and Springs 6. Bridgestone 602 tire. 7. Bark buster. Did not do much for speed but I haven't bent bars or broke a clutch or brake lever since I put them on. 8. BK mod. You know what this did nothing for me. 9. moving my fork tubes up in the triple clamp 1/4" (took some getting use to but I like it now. 10. Actually putting on new bars (taller) was pretty dang nice. It would actually rate 4ish. I have not Done the YZ timing yet but am hoping that it will rank in the top 3.