I did the standard power mods to my 610 the other day, you know LV exhaust and JD jet kit. When I first got the LV silencer I was was a bit concerned. Looking down the throat of the muffler it just didn't look like there was enough perf. in the core to do much sound damping but I was surprised at how good of a job it does at noise management. In some situations it is actually quieter than the factory exhaust with a nice mellow -somewhat throaty- tone when accelerateing. Now as for the JD jetting kit. This is the first time I have ever used one and while I agree that JD does a great job supporting their customers and for someone not familiar with jetting it is nice to have someone put together a "kit" , I am afraid that is where my appreciation for them ends. I still stand by all the comments that I have made in the past about there being nothing magic about the JD kits. While I had everything on the workbench I broke out my calipers and began measuring the fabled triple taper needle. I measured that thing every which way from sunday and could not find any decernable difference between it and the "factory" needle that I removed. I do want to make one qualification here and that is that when I bought my bike the dealer- Bill's MC plus- did do some jetting work prior to me taking delivery. Now according to them they simply changed the main and pilot jet but I guess it is possible that somehow a different needle went in. Anyway the bottom line is that I feel like I paid $80. for a leak jet (could have drilled the blank one), a larger main jet ( can be had for about $5.) and a o-ring. All in all I feel like if you are familiar with carbs and jetting this is not a good value. The overall results of the mods are that the bike has more bottom end snap and a bit throatier sound. It really isn't the OMG I can't believe what I have been missing feeling that some people get. It might be that because mine was so spot on with the jetting that I did not see the gain some might.