My G8 was one of the 1st 10 to be tuned. My G8 has the stealth tune from Vector. It's at the dealership now for a misfire on #8. The tech came out and asked me if I had a chip. LOL
I said no, it has the stock E38 ecm.
My G8 has 17k miles on her, and I have not experienced any transmission problems.
The $20 is above the standard price.