I actually bought some of these plastic rim protectors for my 5th gen "ZL1 style" rims after curbing my wheels for the 2nd time. While getting them repaired at Rimguard, an extremely top notch and reputable company, one of the workers said those have never saved a rim in his experience. His logic was that if you catch something hard enough to deform the sidewall and let the rim get scuffed, there's no way in hell some dinky piece of plastic held by adhesive will hold on. I could not argue against that logic.
P.S. If anybody wants a free pair of unused rim protectors, let me know. You would just need to pre-pay for the shipping label.
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Disclaimer: Unless specific sources are cited, all of the above is my subjective opinion. No warranties, expressed or implied, are granted. This is a car forum, after all.