Upgrades for Rega P3. Worth it?


Good afternoon, all. Have been considering various upgrades to my Rega P3 and wondering if anyone could share their own experiences with this. In particular, looking for real advice on whether certain upgrades were worthwhile and/or had an observable benefit to sound quality to people who've done them.

I currently have a P3 with an Ortofon 2M Blue cartridge, Clearaudio counterweight, and Pro-ject Tube Box SE II phono stage. Potential upgrades I have considered:
Rega TT PSU power supply,
Groovetracer (or other) subplatter,
Groovetracer (or other) acrylic platter (vs. stock glass),
Phono cartridge replacement

Are any of these really worth doing?
nichomoff
Thanks for all the advice! Looks like many folks here are positive on the upgrades. Suppose I shouldn't be too surprised. :)

I also forgot to mention I've been using an old Tri-Pad turntable mat over the glass platter. Have read very good things about this and have been pretty happy with it vs. the stock felt. Anyone else use one of these?

Think over the next year or so I will go for the belt replacement (I think it's time anyway) as well as the Groovetracer subplatter and maybe a Dynavector 10x5 to replace the 2M Blue.
Also kind of wondering what kind of impact the turntable mat has on overall performance. For example, if the mat itself is not perfectly flat, does that simply negate the benefits of a more precisely-machined subplatter?
The biggest bang I got for my P3 was the GT subplatter, GT Delrin platter, and the Michael Lim motor isolation base. And of course, the 24v motor upgrade.
I tweaked the heck out of my old rega planar II, to the point it's not recognizable anymore.

Sure, it performs very well, but I could have spent less on a new turntable.

It was a learning experience and all the tweeks provided better sound, but I could have gotten there much quicker with one single purchase.

Benefit of tweaking - you can do it at your pace

tweaks include...
•SRM/TECH Deluxe Acrylic Platter
•RB250 arm
•Cardas monolithic rewire kit
•Michell Technoweight
•ISOsub GT 2 S UPGRADE SUB PLATTER
•Rega II Motor Upgrade kit
•Audiomods Arm (latest addition)

Hi-fi is a long haul :-)