From a quick squiz it seems the 6cyl M5 is indeed a bit quicker to 100 km/h than was the 5 litre SS sedan, but slower from that speed to higher velocities. Afaik a ute is lighter than the sedan variant, and there is little doubt (and self-evident proof) that the ute was indeed the faster machine around Bathurst. Btw I attended that very race and IIRC there were quite a few Holdens that out-qualified the factory M5
I would consider an approx $20k common-or-garden Holden light-commercial vehicle to be lower profile than a $200,000+ BMW M5 and thus have more Q-value
And I likewise think if you removed all the police insignia from one of THESE it would then (with its plain station wagon looks, bare steel wheels and unadorned trim) represent a lower profile - hence higher Q-value, despite somewhat less outright performance - than something like the pic-attached Merc 500E 'Q-car' beladen with performance-telltale flared arches & spoilers & ground-effects add-ons