Comparing manual trans options - variables other than gear ratios?

A833
A833 aluminum case (and overdriven 4th?)
A855 (Passon Perforance 5 spd)
TKO
TKX
T56
T6060(?) Viper, etc.
Others?

Of your list, the only one one I have heard comments about for drivability is the TKO. Pretty sure they drive fine for the most part, but I have heard of complaints about high RPM shifts being difficult.

You could add the AX15/MA5/AR5/R154 series of Aisin trans to the above list. Not bad options, but not perfect either.

In regards to complexity, the TKX has the option to keep the mechanical linkage. TKO might as well, don't remember now. This might reduce complexity, just depending on your setup.