My buddy Powder Buster runs the mds weights in his pro and I run belly busters and mtx so I have had some descent comparisons. It seemed like the couple times we compared that he would get 1-2 mph faster track speed going up a hill then I would, but he also has a trimmed track and I don't which would account for some of that.
His definitely pulled a little harder I think, but was a little more sluggish when it came to throttle response in the midrange. I think that is due to the aggressive curvature of the mds weight loading the motor harder. I think if he adds a PA or RKT head this summer, which I'm pretty sure he will, it will get that snappiness back in the midrange and the mds weights will work really well.
I was also impressed with how well the mds weights worked over a wide range of elevation. When we went to Laramie this year, my mtx setup that I use in the Big Horns was a little heavy and I wasn't quite pulling the rpms that I wanted. But he was still pulling 8-8100 with his mds weights without changing anything.
I will probably be stubborn for a little longer because I hate the thought of paying over $200 for a set of weights when I can but a set of belly busters for half the cost, but if he starts beating me I might have to give in.
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Honestly I don't think you can go wrong with any of the weights, just make sure you talk to someone who knows what setup you need. Carls cycle for belly busters, SLP for mtx and the guy who makes the mds will give you a good setup for your elevation.