Years of operating a race and service shop in New England taught Turner Motorsport a thing or two about the shortfalls of the suspension system in the 2001-2006 E46 M3. One common failure they encountered was broken rear springs. A problem that plagues many 3 Series of similar vintage, a broken rear spring can easily be identified with a quick under-car inspection (rear springs usually break due to rust in the bottom coil or two) and a lower-than-usual rear ride height is also a normal symptom. This issue is more than an annoyance - it's a safety concern for your Ultimate Driving Machine.
Turner's rear springs are designed to be a lifetime fix at half the price of Genuine BMW springs (which still will fail - again!).?