Russ, MrG240Z,
I used to have a summer job at the wholesaler for Splitfire - and I think they were a bit different - they still have a single electrode, but it has a groove or notch in it. My feeling was that it was a bit of a gimmick.
I also ran the triple electrode type of plugs in my old TA40 Celica for a few years back in the early nineties - never really felt that they did anything that different ... that said I don't ever remember taking 'em back out again and I must have covered about 90,000 miles in it since then ...
Seem to remember that you didn't bother gapping them too ...
Mike