Also, when you right-click a tech and get the popup tech details screen if a tech is a racial tech it should say so perhaps on the first line. "Torian Unique Tech" or something like that.
Yep, even putting the Civ's symbol in the background would be good (or both for a pretty effect!)
For example if the racial tech allows the building of improvements but I could not build them it should be explained or shown with an icon like a red X imposed over the improvement to indicate that I can't build it. So I believe that I as the Humans could build the Arcean Navigation Center but I couldn't build the Yor Charging Stalks. This will help to evaluate if it's worth trying to acquire a unique racial tech.
There isn't anything like that currently. If some tech or improvement is so unique to a race's physiology that it would be worthless to all other races... that tech (or the tech that gives the improvement) just isn't tradeable.
There was once a attribute for planetary improvements that seemed to indicate they were doing this, but it seems to have been replaced with improvements you don't have the techs for being destroyed on successful invasions.
I always go for the Torian research techs as each one is a +5 research and I assume that I get that benefit if I trade for it. But if I don't then that should also be indicated that only the Torian's get that bonus.
Yep, you do. You can even trade with the Drengin or Korath for their version of the farming techs to get those nice +pop growth bonuses. Of course, I think you should get your own race's version of such a tech... just to keep things under control and prevent the
loss of such bonuses if you happen to steal or accidentally trade for those techs from another race...