> Does anyone have an opinion on the likely speed difference between:
> 1. Calling a stored procedure repeatedly versus
> 2. Sending an sql statement to be prepared and then executing that repeatedly.

There is no difference between these cases.

> The reason it is being asked is that (2) allows for a system to undergo change(s) more easily/readily, so the performance impact of (1) vs (2) is interesting.

It is just an illusion. Calling SP is exactly the same operation as
using any other SQL.

SY, SD.