currently own a vpi scout, looking to upgrade

It's a matter of taste and NEVER about which one is better.

Some people (including me) prefer the Rega over the VPI because of the richness and musicality of the Rega compared to the "revealing" nature of the VPI deck.

Please note that "revealing" does not mean harsh or over the edge. It just sound more analytical to my ears, nothing more, nothing less.

I owned the original Scout when it first came out and it sounded superb with my DV 10xGold L/DV P-75 combo. Cannot comment on new model but I'm extremely satisfied with Rega now.

Luckily I have a great friend who owns a local dealer. I visit often allowing me to listen to great tables for long periods of time.

Based on multiple listening sessions, I would only upgrade to a Townshend Rock 7. Again, a matter of preference.

It all boils down to taste and synergy?

I have now had the rega rp8 for over 6 months and it is still the best sounding table I have purchased. More dynamics and resolution over the three VPI's I have owned. One problem with the Rega is the magnesium brace. It has oxidized to a black film. This is common to magnesium but definitely looks bad. I live close to saltwater so I am not sure if this is a common problem.
For those looking for a positive change the rp8 is a good choice with the apheta cartridge

there's a chap called berhard fuss (do a search or pm me) he makes a very good power supply for asynchronous AC motors - they are two phase, have pitch adjustment and are cheaper than the SDS. two phase power supplies are a 'major' AC motor upgrade. Where are you based. Before you change the front end, consider a tonearm cable upgrade - I got a Nordost Tyr and was utterly astonished from the cable I originally had (TCI)

My first turntable was a Rega P25 with Lyra Dorian cart. I sold the Rega bought an VPI Scout (original model). That was a major upgrade. The bass, dynamics, detail level, all improved greatly. However last few years I heard some really great turntables. So I knew there were better turntables out there. I already knew there were more expensive turntables. But know I also knew some were not only more expensive, but also better. So the seed was planted. But if I were to upgrade my turntable I would first need a better phono amp. However in the mean time I had worn out my Lyra Dorian and replaced it with a Dynavector Te Katora Rua.
After trying out a few phono pre amps I bought the RCM Sensor Prelude. Sonically it was tie between the RCM and the Reference DXP SE. There we not the same sounding. Both had weak and strong points. But in the end I bought the RCM since the dealer gave me a better deal.
So with VPI/Dynavector/RCM combination I spinned the vinyl for about a year, year and a half. The RCM was a great upgrade but I knew that it could be better. But how to achieve that without breaking bank. Answer, look for a great second hand deal.
Recently I saw a SAC Girati Grande in a shop, it was at the back of the shop, without a tone arm. After speaking with the shop owner he was willing to get the SAC up and running but the tone arm was a bit of a discussion. Since the SAC came with a SME armboard and the shop didn’t have any SME tone arms. I asked the shop to mount a Kuzma Stogi ref 313 VTA arm since he had a 2nd hand. I think Kuzma makes great arms. Someone I know advised me a Dynavector 507mkII arm. However I was not hear of it. I wanted the Kuzma.
A date was set for me to listen to the SAC/Kuzma combo. When I arrived at the shop I saw to my dismay thath the 507 was mounted. Nothing then and there that I could do about it. So I listened and I could not deny that the combination was great. It was better than I hoped for. This was about 3 weeks ago. Soon the SAC will be delivered. It needed some final tuning, new belts etc.
So I would advise you, visit your local dealers, see what they have, listen then decide. I would not by VPI upgrades. The SDS while it is great is overkill for a Scout and adding non VPI upgrades may or may not work well.