Which upgrades for my Rega Planar 3?

Look into the Graham ones, by the way what is your budget.

Boston Audio Mat1 platter mat - $199, Mapleshade Heavyfoot cones x 3 - $120 into a Mapleshade Maple Platform - $75, suspened on sorbothane squares - $20, Kerry Audio Design F2 counterweight - $129 and Acrotec armwire straight thru to male RCA - $150.

Well there you go ,take your pick....or picks.

I upgraded my son's Rega with these sorbothane feet, and he describes the sound as "more detailed"   https://www.mnpctech.com/products/rega-turntable-sorbothane-isolation-feet-set-of-three