If I was going with a MII, I too would go with the R&C. I have no experience with any of them but I have seen the Heidt's up close and wasn't very impressed. One hot rodder told me he lost his right front wheel assembly because the mounts broke. He showed me the modifications he had to make to fix it. This has been a couple of years ago so maybe it's no longer a problem.
There seems to be a lot of extra parts you have to buy with the Heidt's and the bottom line is very close for the two mentioned.
If you have the time and talent you can do it a lot cheaper by buying the R&C cross member and building it yourself.
If there is another project in my future that's what I will do.

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"Tell it like it is or don't tell it at all" 1964 Falcon 2dr HT, 347V8 4V, dual exhaust, 5sp, pwr assist R&P steering, AM radio, heater with defrost and 2sp fan, electric windshield wipers, cigar lighter, dlx light group, bucket seats, console and full carpet.