Range Technology AFM Chip

[SLong]

Have any of you guys heard any reviews on the Range Technology AFM Chip? I did a little reading and it claims to keep your truck in V4 mode more of the time, enhancing mpg from 1-3 miles better based on how hard you drive. I have a 2011 Z71 with 67K miles and haven't had any problems with it. Just curious to see what your thoughts are on this chip or if anyone has any direct feedback. It doesn't void the factory warranty. Thanks.

[RyanbabZ71]

http://www.gm-trucks.com/forums/topic/150751-disable-afm-without-tuning/