I reckon the only 'Ring' record that really matters anymore, is Bellofs.
6.11 unofficial in quali, 6.25 ish in the race, IIRC. Although he did end up upside down.
That fezza doesn't look to be a standard production model, more like an engineering testbed. 'Production derived' says it all. It's basically been all max powered up with one of those electric computer fan style turbos, a carbon fibre gearknob, 19's, slammed, and flip paint.