Not really, a lot of people into cars who don't do much more than plonk around to the shops like the idea of using optimum products, fuel oil etc. Given the choice of a range of products, it's surprising how many people choose the fundamentally better and more expensive products even telling them they probably don't need it.
Speaking of fuel, another engine the knock sensors pull ignition timing out on 91 big time, is the BA to FGX 4.0 litre Ford Barra engine, but on 98 there's no knock sensor intervention.