Bump.
I put the case of the Lucas Synthetic 5/30 that I have had for the last year or so into the GTO last weekend. A series of coin tosses chose the Lucas over the other stuff in inventory.
It was certainly packaged in a premium manner; thick bottles with a foil seal under the cap - haven't seen the seals in a long time.
The LS1 seems to be nice and smooth with it, hasn't grenaded in the last week. The on board computer reports a 0.2 mpg gain over the Havoline Synthetic 10/30 that was in it, but it's too early to consider that reliable.
I recall it being pretty expensive stuff, so I'll run it until the OLM says to change it out.