Good question. If it was a TNT 4 then it was probably the white acrylic platter. My experience with my TNT HRX was that the acrylic platter (translucent white) was livelier and had some accents in the highs. With the Delrin(?)/Aluminum Super Platter, the bass was fuller but a tiny bit less articulate and the highs were a bit softened. I've not seen the new classic platters. So IMO only, changing platters would depend on what sound you are shooting for.
The Stogi Ref is a good arm that handles mildly warped LPs with ease. The periphery ring with the matching heavy clamp however works magic on LPs that are badly warped but can't be replaced. I have enough of these to have warranted my purchase way back when. As for using it on LPs in good condition, with all honesty I can't say the differences, if any, were all too audible, then again that might be because I'm OC when it comes to leveling the rack, the plinth and the armboard.
Ideally I would recommend you get both but I suppose only you can determine which is of greater priority.
Have fun!