Aren't you worried about hitting the front end with it lowered? I forgot I had the front lift and hit the bottom leaving the Hotel Vancouver. Nothing serious but it sure sounded awful. Couldn't wait to check when I got home
Like some on here, I am not a stranger to lowering my vehicles, previous ones mostly had Eibach springs to get a 1" drop, and my last project, the family VW Atlas, has coilovers with a 3.5" drop (and much larger rims). My rule of thumb is simple, the gap between the top of the tire and underside of the wheel well should be no more than 2 fingers, using the 2nd and 3rd fingers, inserted straight into the gap (not up at an angle). That should yield about a 2" space, maybe 1.75" for some of you with smaller fingers. With a 1.75" to 2" gap that should allow for enough spring compression to get you out of a bind for bumps or if you need to load up some more than average weight in the car. For my truck my coilovers have a compression of about 400lbs per inch which means I can trailer about 4000 lbs, have it drop an inch, and still have some safety space left above the tire.
When I went to visit Ciocca in the US, I immediately did the 2 finger test, and I was shocked to find out that the stock ride height was already quite low, my 2 fingers fit nicely on top of the tire without too much space above it. So many posts with people claiming that the C8 sits high like an SUV or monster truck, but I did not find that to be the case in person (based on my 2 finger test).
However, I do like that slammed look with very little wheel well gap, which is why my mind is spinning trying to decide between collars (front lift) and a coilover drop in back, and keep it simple, or go with Eibach springs for a solid 1" drop but likely stiffer ride. In speaking with a couple of you who have done springs in the past, the feedback was don't do it Neil, you will not enjoy the ride, teeth will rattle, even with MRC. My eyes will probably prefer the look of the drop springs, but my body (and my wife) will likely appreciate the delicate drop yet comfort of the collar/coilover drop setup.