[Christ]

Can you measure the spring force of the XFi's OEM ring?

If you can find a way to measure how much compression is necessary to close the gap, which is almost how the XFi's rings would be installed, you can get something close to that w/ the D-series rings I sent you. You may actually find that they're very close to being the same.

The problem I see with stretching the ring and heating it is that they are bi-metal rings (almost universally, anymore) and something might react negatively to being forced into a different shape without proper tempering techniques? I'm not a metallurgist, so I can't say for sure...