Upgrading from Rega P5 TT

Keep the P5 and add the metal aftermarket subplatter.
I own a P5 too.
And yes the P6 would be basically a lateral move.
Spending the money on the subplatter would be better.
Do you have the separate power supply? add that in too.
Go for a better cartridge..
A better phono box
I use a Benz Glider with my P5 ($1,200)
And a Bryston BP1.5 phono ($3,000)
So I would say from looking at your other gear, going to a better table is not going to do much, until you improve the phono box, and cart anyway...

I have the GT Subplatter, counterweight
power supply
GCPH phono
10x5 Dynavector cart.

Maybe I should upgrade my cart, budget would be $800-1200
or
sell the P5 and pop for the P7.

I want to thank everyone for their input.

Get away from Rega while you can. By the time you do all the upgrades (I've been there) you could have a new Well Tempered Simplex. I have an Amadeus and I hear the Simplex is almost as good. The Rega is not in the same universe, even with all the upgrades.

The P5 would be a lateral move, as others have said. Also, many people do not consider the P7 enough of an upgrade over the P5 to justify the price increase. Most say you need to step up to the P9 to significantly upgrade.

Whetstone audio in Austin, TX has a P9 for $3K. Brian is a great person to deal with.