Basic cons are 60 mps, enh are 80 mps. For GT, basic comes out at 90s and enh comes out at 120s (after the 120s research completes).
Generally speaking first cons for GT will build somewhere between 4 minutes and 6 minutes in game time (this has been thoroughly tested) if they travel 2 sectors. This means that basic cons have a travel time between 2.5 minutes and 4.5 minutes. Enh cons will travel, then, for 2 minutes to 4 minutes.
In 2.5 minutes a basic con will travel 9000m. An enh con will travel 9600m in 2 minutes.
If the rock you want to plant on is exactly 6k away, the basic con will plant at T = 190s. If the rock you want to plant on is exactly 6k away, the enh con will plant at T= 195s.
Advantages for leaving GT cons as basic:
-Saves 4k
-First TP builds faster if you're building the TP at home or just one sector over
-People who don't understand math won't accuse you of "embarrassing" yourself
Advantages for enhancing GT cons:
-Cons get to further positions faster meaning more secured map
-Cons are a fair bit harder to kill with 360 additional HP and .25 less sig.
I don't begrudge Terran for liking to hold on to the 4k of course
