Well I ran slick 50 in my cosworths after engine rebuilds and running in and I run it in my scoob and any other performance car I've owned, I personally believe the marketing and to this day I've not had a problem with it, I've no evidence either way of course, but I feel happier thrashing the as-s out of the cars with it in, I'm obviously older and calmer now so the scoob gets a mild ragging, but the cosworths and the gto especially got thrashed on a daily basis
i don't go for anything else like oil stabilisers etc I just run decent oil and change every 3000, I did just run redex advanced injector cleaner tho
Tbh if I'm thinking of buying or doing something to the car I will research the ins and outs for weeks and I'm a bit sceptical of most things, but I thought I would give the grounding kit a go and see, and for me it has worked, even the idle is noticeably smoother, I'm not trying to promote a sale of one in particular as I made mine myself, I just thought I would share my personal experience 👍