Mine isn't accelerating like I expected it to either. I'm guessing the 9g weights are too much. I did get a couple MPH on top end but it takes forever to get from 30 to 40 indicated. I used to top out at 37ish.
I'm guessing because the weights are too heavy, it's taking it too long to pick up RPM. However, the better roller ratio of the Multivar gave me about a 3mph gain on the flats, it just takes longer to get there.
I've got some 6g Ninja sliders on the way. I'm hoping this will help out the acceleration (and maybe add another MPH up top).
Next for me will be a more aggressive torque spring. I didn't install the white one yet, but everything I've read tells me I want one that is just below the race spring (the 82% purple).