I don't have one but I do have an opinion
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Until it was fully described what the product was, I didn't see the logic in the extra cost of the guardian over just replacing the bearing.
However, I think the product is just marketed incorrectly. It's really an engine guardian that can detect any abnormal wear of all the bearings and ferrous metal contact surfaces within the engine. It should be marketed as such and should be marketed to ALL passenger car makes and models. Then your talking about a device that will give early warning of insufficiently lubricated pins, guides and bearings in any car.
It's much more valuable and useful than the AFR gauges and oil pressure gauges the people put in their cars but don't know what they mean. I'm now a convert.