I find 1800#/' torque spikes a bit high. And under full load on a dyno, I highly doubt they ever get close to the 413 that the LF-16 can handle.

But that aside, the coupling that's shown in the KH picture looks very similar to the standard BMW or Mercedes driveshaft flex coupler between the driveshaft and the differential. If so, this is probably close to the one originally used on the Harley MMC comp. I have one of these and it does flex/bend ever so slightly, but there is no flex in it radially at all. There's actually a hard disc laminated around all the attachment bolt holes so it transfers torque directly, but able to flex angularly just a bit.

Can't see how this would be much better than just a solid coupling for torque pulses etc.

[Linked Image]

Dan