"...there is not a way to update from a leak."
That statement confuses me. A 'leak' and 'RUU' are the same thing, correct?
I flashed the RUU that MrSmith linked to
HERE. I guess you're saying that I (we) will probably be able to receive the OTA if the official OTA has a larger version number.
So a leaked ruu, or any RUU, is the entire ICS rom. It's a file about 550MB (maybe 600). The update will be a 300MB file that takes and replaces files from gingerbread it does not need, and replaces them with ICS files. So the problem with getting the OTA when your on a leak, is you already have the files it wants to replace. There will be a RUU for what ever the official OTA is, so you'll be able to update that way. If you wanted to take the ota, you would have to s-off, then you could downgrade to the last official ota, then take the upgrade. I'm not sure why you would do that if your not roming and modding, but it's another route.
The only bad thing about doing the leaks, is when you RUU, it wipes your internal memory, and you have to set your phone back up. If you do the OTA, it pretty much keeps your phone the same as it was before. On the flip side, when you run RUU's, you won't have any problems, unless it's a known bug. Check the Razr forums, quite a few people had to do a factory reset anyway ofter taking the OTA, so they are in the same spot you would be after running the RUU.