FYI, all 8BA era pumps came from the factory with spiral impellers.
I first encountered Speedway pumps 20+ years ago soon after they came to market. I was impressed with the new castings, sealed bearings, and ceramic seal. I have never had a problem with them, and know of a car with a set that is now 20 years old and still working well. I have also had friends sent off pumps to Skip for rebuilding, both a head mounted water pump set for a 36 and a Lincoln-Zephyr set for a V12, and have been impressed with Skip's work both times. I think you will be fine with either decision.