I just installed a set of Brisk Premium LGS and it did make a difference. Idling is smoother and there is a noticeable improvement in the acceleration and engine feels more torquey.
I was using those ordinary Bosch platinum plugs before changing to NKG Iridium IX. I didn't feel any difference at all. After that I tried Denso Iridium (they boast their 0.4mm tip is best blah), no difference as well. Changing to the Brisk LGS makes an immediately difference.
The only downside is that the plugs are extremely expensive. I bought 4 of them at Atuobacs at $176 (I am sure elsewhere is cheaper).
Brisk USA Enterprises, LLC
Well, I guess its one of those rare times that a product did work as advertise..lol....