@rvpiano The one limitation with Rega table/arm is fixed VTA.. When I replaced a worn out shelter 501 with Ortofon Quintet black on my RP6 I was very disappointed with the sound and was not hearing anything that glowing reviews said about quintet black. Ortofon being much taller than shelter was the problem. I had to raise the arm base by almost 5mm to get it sound better but still not the sound I was used to with Shelter. Once I replaced RB303 with Audiomods Series VI arm with micrometer, quintet came to life. It sounds excellent now. The only other mod done to the table was replacing stock subplatter with groovetracer.
As other have said, isolation/leveling is extremely critical. Regas don't like sitting on heavy platforms.