I have a question for all you transmission experts. I am planning to change out the filter and fluid on my 99 GT and my brothers 03 GT. I have done it before on my 99 and I figured I would do both at the same time as regular maintenance. I searched on here and on other sites researching the swap to dexron VI. I have read good things and bad things about switching over to dex VI. I was wondering if any of you guys who have switched over have had any issues?

Specs on both cars.
99 GT with ~86K miles
03 GT with ~65K miles

Thanks,
Mike