Need suggestions for a TURNTABLE MAT...

The only aftermarket mat to ust on that table is the DNM ringmat. It does not dull the sound at all and brings up the contrast a notch.

change your glass platter for the acrylic platter and use no mat.

I used to have a Rega 25 with rb600. The ringmat was a big improvement. Ditto for the heavywight. Everyone once in a while you'll see them used here for about $50 bucks each. Well worth it for that kind of money.

Agree 100% with Jfrech on both the Ringmat and drop counterweight (Heavyweight).

If you want to experiment cheaply, you might try the cork turntable mat that sells for around $10 (I think Audio Advisor sells it). Depending on what kind of sound you want (somewhat lively rather than heavily damped), this mat is surprisingly good.