Having purchased our first Tesla years ago (2012 S P85), have been watching S pricing since the beginning.
With two exceptions, Tesla has generally maintained roughly the same price points each time they make model changes, providing more range or features for roughly the same price.
The two exceptions:
- When AP2 was introduced and they started charging for AP and FSD, those features increased the price of a fully loaded S
- When Tesla started losing the full $7500 tax credit and they began selling 3's, they did around a 14% price decrease for the non-performance model and even a larger price decrease on the performance model
Tesla has positioned the S/X models at a rough price point above 3/Y and in comparison with comparable luxury ICEs, so it would be surprising to see the price change much when Plaid is increased. The fully loaded performance/Plaid version may cost more. But if they make any "refresh" changes to the other S versions, it's likely prices won't change much (and might even decrease, if the changes reduce manufacturing costs).
Tesla usually announces model changes when those changes are ready to go into production, and then have to deal with customers with orders which have been placed and not yet delivered. They usually don't make any pricing changes for orders immediately before a model change is made. While there is a possibility Tesla might reduce the price of any inventory vehicles they have after the changes gone into production, but you can't count on that.
Every time there is a major change to one of the Tesla vehicles, there is always some angst and frustration from customers who received vehicles immediately before the change and uncertainty by those who have orders in process. This is the trade-off for Tesla's practice of introducing model changes immediately when they are ready to go - rather than waiting for a new model year...