BR9EIX are actually Iridium, not platinum. I'm convinced they are far superior to platinum for my car. I was going through one set of wires per year on platinum plugs. I think it's been six years now since I did the wires after switching over to iridium. On a 2 stroke I'm not so convinced there's much benefit. I've been using them, but it's a little pricey when they get fouled so I switched back to EYA's for now. As for performance an average rider probably wouldn't see much difference.
I've read that alot of people think they are beneficial. Personally though, I ran 'em in my '98 ZR and found little benefits. I fouled 'em as well and went back to BR9ES's...(which I have a bunch of for my other sled).