I’ve had the JRi on the RC390 for several months and I’ve ridden with it at several tracks. It’s improved the RC390’s handling quite a bit, but it’s also exposed the fork as being sprung too soft and inconsistently damped. That’s kind of the way these things go: You improve one thing, which reveals weaknesses elsewhere. Luckily, I really enjoy developing and tuning bikes, so I’m up to the challenge. I’ve already got the fork upgraded, but that’ll have to wait for another update.