The 6.9 hasn't got the racing heritage of the GTHO.
That is why they bring much less at public auction.
I would much prefer to drive long distance in a 6.9.
That is what they were designed for.
To drive Sydney to Melbourne in a GTHO would be a much rougher ride, and would be far more tiring to drive. Perhaps much more fun with throttle response, and a sound track to turn heads.
Combine the two:- how about a Sbarro 6.9 GT?