I just purchased a used, "stock except for 437M wheels" 2018 M3. While static, I notice the rear end visually appears lower than the front. Searching threads here, and some stock Google images, that appears to be largely factory...but I'd like to verify that these measurements are accurate, since the rear tires look almost tucked especially compared to the front end (photos at bottom of post).

The car is on 255/35ZR19 front and 275/35ZR19 rear.

Driver
ground to fender - 27-3/8", or ~695mm
bottom of rim to fender - 25-1/4", or ~641

Passenger front
ground to fender - 27-1/8", or ~689mm. I hope variation L to R is due to my poor tape measure skills
bottom of rim to fender - 25-1/8", or ~639

Driver rear
ground to fender - 26-1/2", or ~673
bottom of rim to fender - 23-3/4", or ~603mm

Passenger front
ground to fender - 26-1/4", or ~ 667mm. I imagine variation L to R is due to my poor tape measure skills
bottom of rim to fender - 23-3/4", or ~603mm

Secondly, I've found multiple full-replacement air suspensions, but does anyone know of a M3-compatible helper air bag kit like the AirLift 1000? I am not looking for adjustable suspension; just for a little help preventing squat while towing.