If we're talking about the same thing? I have a new Cadillac XTS with the adjustable seat extension. I am tall also with long legs and this works perfectly for me in the Caddi. However it is a waste to think its of any value in a C-7. My legs are propped up in the cabin of my C-7 and would never touch the extended seat if equipped. I am 6'3" and with the recommended seat adjusted, per the Forum, fit just fine. The most fun car I have ever owned.
Cyber Grey, Born Oct. 29, 2LT, Nav, Auto, Z51 Spoiler.