REGA Planar 2 with RB250

I just acquired a used, but immaculate rega planar-2 with rb250 and ortofon 2m red. This is a very synergistic setup with performance unexpectedly very good. By no means am i about to complain about what i have, but to ask the diy public why my other planar-II did not perform to the height of the rb250 setup. A few years ago I purchased a planar-II it had the original shiny steel 'S' tonearm which just begged for upgrades. My first upgrade was a rb220 purchase. Next item a machined aluminum sub platter kit. Another upgrade was from an online conversation with Peter Riggle who sold me a vtaf kit and finally a felt mat. All these had various degrees of improvement and i was quite satisfied until my motor began a speed problem. Not measurable, but audible. It would slow at times then back to proper speed. At that point i wanted a new motor and for some reason I just couldn't locate one. My issue! When the new 'used' planar 2 arrived, right out of the box, this setup just blew away my original table with all the add-ons. So, what was so wrong with the original table? Could it be a new speed controlled motor replacement, maybe the DC motor from REGA? Or, was it the plinth? Table setup?
 
rayma, i'll try swapping out the stylus and the cartridge... Through process of elimination I hope to chase down the problem. Trying to be logical, there are two possibilities I haven't approached... A new motor, in this case it should be the REGA DC motor. And if just to improve...a MDF plinth!
 
this being a DIY site, you can piece together a better motor solution than the stock rega motor kit, for less money.

i use a Brushless 3-phase motor from Anaheim Automation ($100) and an Arduino ($25) + motor controller board ($25) to send a perfect 3-phase sine wave to the motor. There is also a member here who supplies a custom designed all-in-one board for 3 phase control.
 
rayma, i'll try swapping out the stylus and the cartridge... Through process of elimination I hope to chase down the problem. Trying to be logical, there are two possibilities I haven't approached... A new motor, in this case it should be the REGA DC motor. And if just to improve...a MDF plinth!

Don't swap the cartridge, just the stylus. The bodies are the same.