I have for the most part over the years used Bosch in my autos, American & the 1 Mitsubishi I had. But within their line I found that the cars are happier with the Copper core plug (Super plug) than the Platnium. I will admit the Platnium plug runs the engine a little smoother, but I get beter performance with the copper plug. I've had a few Fords, a few GM'* ('70 Chevelle, '97 Boneville and a Chevette - don't tell anyone) and the one Jap.
The Bonneville had the GM iridiums in it, I just recently replaced them with the Bosch Super, didn't have the cash to spare on the pricer plugs right now.
What I want to try, when Champion comes out with them is their Premuim Gold Iridium plug. Supposed to have a coper core with a iridium/gold tip. Will be a killer plug. But I haven't seen them available at a retial level yet.
I've never found a big difference in wires, but then agin I haven't had the spare cash to lay down for $50+ wires. Always been content with the Bosch wires. That'* what the Auto stores in the area carry mostly. Have tried generic, didn't see a diff to speak of.
OK THE SCIENCE LESSON
In general the electrical conductivity of copper and iridium are far superior to platnium.
But platnium and iridium have a better durability than stright copper. And gold has a durability up there with platinum (a little better actually) and electrical conductivity near that of copper. Hence Champions idea for the Gold Iridium line, with th copper core.
So don't get to hyped on Platinum as the best plug:
If you want long term durability- Platinum.
If you want a little better performance and don't mind changing the plugs once in a while go copper.
If you have the money go the iridium route, they use a copper core and have good performance.
Brand loyalty is upto you.