I did try the THX Optimizer stuff for a viewing of ANH one time ('04 DVD, for reference), and I can definitely say I preferred the colors that gave me versus the stock settings on my TV, even despite the slightly limited settings I had to mess with. Not a massive difference, but I recall that it was a bit more natural-looking.
If you still have that THX equipment and have the 2011 Blu-ray, I ask you to try to see if there is a difference. I repeat, this technology was included in 2011 and STAR WARS was the first to use it.