I believe it is definitely possible to lower the ZL1 an inch or less with the MRC as many CTS-V owners have done this and kits are available online. Currently D3 claims it has the only lowering kit 100% compatible with the OEM mag ride shocks:
http://www.d3cadillac.com/products/d...rings-cts-vcts
I will wait at least a year before making any performance mods to the ZL1 just so I can get a handle on it stock form; that way I can fully appreciate any changes I do make...I'm sure by that time there will be a quite a few aftermarket options to choose from as well
But lowering the car 1/2 inch or so is defintiely on my "to do" list
