Platter for Rega RP3 turntable

I've just begun making tweaks on my Rega RP3 turntable. I ordered a new subplatter and improved belt.
in addition, would an acrylic platter make a big difference?
I've looked at the ads for the Groove Tracker and the SRM/Tech platters.  Is there a significant enough difference in the two to warrant the big price difference?
Are there others that anyone likes better?
i would appreciate any feedback.

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Thanks, viridian.

I think I'll save the money and stick with the glass table with the Herbies mat.

I have extensive experience with the Rega tables and have tried many different tweeks.

My favorite platters (in order) are:

1.  Funk Firm Achroplatter...the best, period.  I don't think they make them anymore, but still make the Achromat platter mat.  One of the best mats available.

2.  The GrooveTracer Delrin Platter

3.  The Shear Audio/Iron Audio acrylic platter

4.  The Rega OEM glass platter
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I see that the Achromatic platter mat sells for a little over $100.  I'm thinking of buying it based on MoFi's recommendation. I can always return it if I don't like it or it makes little difference.
It's amazing what a little tweak can do.  I just yesterday got the Rega white belt, and the improvement was amazing.  All of a sudden the imaging snapped into place and the sound became fuller.  The bass even improved. I never would have believed it with just the change of a belt!
i originally mistakenly ordered the Edwards sub platter.
I haven't read any good reports about it, so I ordered the Tangospinner from Argentina which I've heard many good things about.  I haven't gotten either of them yet, but when they arrive I'll try and compare them and return the inferior one.  I know the Groovetracer sub is the most recommended but it's more than I want to spend.
viridian, Your certainly right about the dollars adding up, but for a few hundred dollars it's cheaper than buying a better table.

Another improvement I was thinking of was the  Rega TT PSU.
But at $400, it gets a little expensive.
Also, how much better can the sound get!?

P.S. I ordered the Achromatic platter mat.

Huge improvement, much more than the platter upgrade. Lower noise floor, increase speed stability, improves timing, plus you can change speed at the touch of a button.

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A lot has happened since my last post. 
1. I received the Achromat platter, and unfortunately didn't like it. Although it was very detailed, it seemed to cut the overtones from the classical music I listen to and didn't let the music "breathe."  My Herbies mat was better in that respect.
2. I ordered and received the TT PSU but I haven't heard it yet because:
3. One of my mono block amplifiers (NuForce) stopped working and unfortunately the manufacturer is out of business.  After much Googling, I found an ex NuForce technician who is going to repair it and upgrade both amps. That's the good news.  The bad news is I'm without any sound and am unlikely to have any for a total of two weeks.
And this after I ordered several tweaks that I can't hear!
Audiophile Hell!!!
I have a Iron Audio acrylic platter. (approx. 1 inch thick) in like new condition if you are interested. To my ears it made a nice improvement on my Rega. Don't use it because I now have  a Well Tempered Labs Amadeus Mk.II.
I'm a little bit wary of acrylic after my Achromat experience.  I think I'll stick with Herbies for the time being.