[copbait73]

Here is one more data point that may trigger recollection.
Tonight I was reviewing a file I collected in the '90-'91 timeframe. At the time I was investigating improved turbos for a guy's 930. Here are my notes:

415HP, KKK, 5327.970.7006 $700
500-550HP, KKK, 5327.999.9301 (RUF) $1000

Unfortunately, I had little interest in KKK turbos at the time so don't know the aero details. I ending up buying him a Garrett Buick GNX Stage 2 unit.

Interesting to me, here is the "999" notation tied to a RUF turbo configuration.