Jim,
The thing that sticks out to me (no pun intended) on this set-up, is the size of the hub which is going to protrude through the wheel. Don't see how one could run center caps on a Rally I or Rally II with those hubs. Doubt that a set of Rally II's would even fit as the center hole is small. Also doubt the ECI hubs would fit with a set of Hurst wheels & caps. Basically see this as decent option, if one is set on running aftermarket mags that have a big centering hole in them & the front suspension has been recently rebuilt completely with quality parts. If suspension has only been partially gone through, or suspension parts are cheap Chinese replacements, there are other options.
The rest on ECI set-up looks fine, design wise. The rotors & calipers are common serviceable GM pieces, not dependent on one off race style aftermarket pieces, where if the company changes it's product line, or goes out of business, one is left holding the bag, when one needs replacement parts. At least to me, this very important. With klast year or so's track record of new fangled aftermarket disc brake conversions being brought out nearly every other month, def something to think about, as when this market goes stagnant, there will be some weeding out of product lines & eventually businesses.
Hope this helps, not trying to be negative, just trying to give honest & humble feedback.
