I never thought of sport mode and light acceleration at the same time. When it's in sport mode, I'm having fun.

Driving normally I average 17-18MPG according to the computer but a lot of that is highway commute.

I'm wanting to replace my torque converter soon. I'd rather pull a transmission and pay for a new converter than ignore it for too long and have it take out the transmission too. There's definitely a cost ratio to consider.

I wouldn't add a thing other than approved fluid to a ZF. Eff that, too temperamental and expensive. Which is typical German stuff really.