I still have four bottles of the blue...
Trade for a /6 engine...?
The SL.6 is a low-viscosity version of the ATE200 "Amber". It's primarily for ABS-equipped cars for quicker response.
However, it's perfectly fine for use in our cars, though note that the wet boiling point is ever-so-slightly lower than the ATE200 (only 10-15 degrees). Perfectly fine for street use.
I've used ATE 200 (and whatever Blue I have left) in my street and race cars for decades.