Well, for diagnostic purposes, I swapped an auto 2.59 chip for an auto 3.07 axle ratio chip. It wasn't the chip, but a previously intermittent problem became a permanent code and helped troubleshooting the problem. I guess we got lucky on that one.

With auto probably being 2.59 and manual 3.45 axle ratio, I doubt it would make any sense for Dads90 to swap chips.
I would assume, using an auto chip in a manual set up is not so much a problem as vice versa.