Rocky, you will still need to use your reflex clamp. The vacuum improvement will be more noticable on some records than others, on a flat 180gm disc there will be very little difference btwn the vac on or off but on some records the difference is bigger and this of course depends on the resolution of everything downstream. As far as the motor is concerned the more accurate the speed stability the better the sound period. I dont think any one component or change will generally yield a large "wow" factor, improvements are usually incremental and in high end audio the magnitude of improvement is generally over exaggerated when being discussed.
Rick
Rick