[WVZR-1]

Knowing what you've been through and have done chasing the issue I'd think your only reasonable diagnostic tool would be to do a ride along with someone or drive along and if you find a car that "suites you" (not meant in sarcasm) at speed, you then take those tires and wheels to your car and see if your car still has the same issues or not. There is no other economical or feasible way to accomplish it.

It would easily be worth a couple hundred mile drive to evaluate another car. You mention before hand the speeds that are your concern or where it's most notable. Have that person pass on to you that his car passes the test he feels and you then do the drive.

If his to yours passes the test you move yours to his car and see if the same scenario plays out on his car. Two tire swaps and the diagnostics are done.

I would think I'd be interested in doing this with someone that has recent tires and maybe stock wheels or if the wheels are aftermarket that their "hub-centric" because there's a few less hassles although as it's been mentioned there's nothing wrong with "lug-centric" and regardless of the center-bore Corvettes are actually "lug-centric" although it's done on wheels that are very close to "hub-centric"!

A good day of driving, lunch or whatever and it's done/over - no more diagnostics.

If you only wanted to do the swap one way from a car to yours you wouldn't need a ZR-1, just a C4 with newer tires, stock wheels and "no issues"!