I agree with with a poster in the other thread, the 6 speed is more of a bragging thing than useful unless you build the powertrain around being able to pull these gears.
I also agree with this guy. I looked at a T56 built by XV for my 'Cuda but after thinking about it, talking to Scott and doing some research, there isn't any real benefits for it other than to say you can swap one more cog than that of a 5-speed driver. Only good thing about a 6-speed is if you cruise the interstate or open roads for huge distances then obviously the 6-speed comes into it's own. Still, the 5-speeds are no hi revving animal and cruise very well too.
Anyhow, I stayed with the 5-speed over the 6. Nothing to do with money or the extra work required to fit it, I just didn't see any reason to other than a little bragging rights but that is of no concern to me. If they are all tied up over a 5 or 6 speed and aren't under the hood looking at the Hemi then they have real problems lol.......but, I guess it comes down to preference, like most car things.