standard counterweight vs drop counterweight

To me it was a no Brainer, even though I have heard a good set up(Nottingham Horizon, Shure V, Rb250) without the endstub upgrade. Between the two mentioned above I would have to go with the F-2, from Kerry Audio.

I had both the Express Machining and the Kerry Audio counterweight at one time, I kept the Kerry F2. I tried both on a Rega P3 before I got rid of it and the Heavyweight. The listening test was b/w a RB300 w/ the EXpress Machining Heavyweight vs. the RB 250 WITH Express Machining 2xtreme endstub with a Kerry Audio counterweight. Do not take this as a TRUE test since they were on diff. arms(another debate entirely) I felt and heard more extended highs with the 250 arm, though. Now, was this the endstub, counterweight or the 250 arm(lack of spring) who knows? I hope this muddies up the issue for you.;)-~ The F2 from Kerry does have ridges that the counterweight rides on while attached to the counterweight, tightened by a plastic? screw down bolt, instead of metal(at least where it contacts the endstub). This may help with the resonance issue?