I've had the same set of plugs in my 944na for the past 11-years!!! May be longer as that's how long I've had the car and haven't even changed the plugs. Performance-wise, copper is more conductive than either iridium or platinum. Those are really just for durability and longevity.

Nissan V-6's in some of the small pickups are the worst. I've had to use two 12"extensions, and 2 u-joint adapters to get to a couple of them on that engine....

Page 90 in the Owner's Manual (1983).

http://forums.pelicanparts.com/uploa...1492647894.jpg

So the best NGK spark plug for 16v engine is BPR6EIX?
How about BPR7ES?

Thanks in advance :)

I read the OP's "'86 944s" to mean plural, or multiple 8v 944. The later 944S 16v models use a colder plug. Here's a listing of compatible plugs: 1988 Porsche 944 S Coupe - Ignition Tune-Up - Page 1

Yes, the s meant plural. I have the base 8v 944 in both cars.