Yea.....I don't know about the PSI twins on the Exciter. I had a modded out 91 that had about everything that could be done to the motor, clutches, bored carbs, pod filters etc, etc, etc. It was supposedly dynoed ad 120HP.
Sure didn't feel like it though. Very soft and smooth. Thing didn't pull very hard at all, but it had LONG legs. I don't know what it had for gearing, but when it(rarely) ran decent, it ran, and kept going, and going, and going. I hit 121 or 124 on the dream meter. That was at 9400 RPM. As soon as I saw 8500, I kept a close eye on it remembering that my stock Exciters were done at 7800-8000. I figured 9400 was enough, so I let go of the flipper.
Preferred my clutched otherwise stock 88 over the 91.