Generally there’s a recommendation for a given engine and naturally there’s overlap between engines too.
The plugs used in two stroke kart engines are not typically used in road cars. Mainly because the specific output (and therefore heat) of two stroke engines tends to be higher than a road car four stroke engine. Plus we’re on full throttle for much longer.
My personal advice is stick to the NGK range of products for the sake of simplicity. The quality isn’t a question. You’ll find yourself usually on an NGK in the heat range of 9 or 10, vs their car range which tends to be 6 or 7, even for boosted and other high performance applications.
Four stroke kart engines tend to be in that same range of 6-7.
Here’s a topic to mull over too.