Cheeze,
As a consequence of rainy weather I'm been switching back and forth between my shoes this week. And, because I'm in the process of setting up a new bike with 200mm cranks I've been paying extra close attention to my shoe set up, ankling, spin, etc. This has highlighted that there is a stack height and heel height difference between my Sidi's Genius' and my Shimano R86's. Keep in mind the Genius' are a couple versions old and Sidi has no doubt changed their sole patterns. And, Shimano is now up to R88's in their 80 series.
But, the Sidi's have a thinner sole with lower stack height and less high heal built into them. We're not talking about lots of difference. It's only a few millimeters, but, I thought you might be interested and that it might influence your purchasing decission. Although, I can't comment on the current Sidi soles.
I tried to get some photos, but, couldn't come up with a decent photo that did the situation justice without simply relying on lense angle.
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Birth Certificate, Passport, Marriage License Driver's License and Residency Permit all say I'm a Fred. I guess there's no denying it.