You will not get any better MPG. My 99 Full Time has the option of selecting 2wd. Myself and others who have the same drivetrain have found negligible to no difference between FT and 2wd. Yes you can remove the drive shaft with no issues. R/T Mark who post here did a test on the durangoclub forum where he took off the shaft and found no difference in mgp. Even if there were a slight hit in mpg for having FT or AWD, I take the the trade off for safety any day. That's why I got the FT option.