Just my $0.02. Try asking your service advisor at your local Mercedes Dealer. Some advisors/dealers are cool and actually refer you to places they know are reputable for this kinda of stuff. Few years back the Downtown LA Mercedes referred me to Globe Tire by West LA for rims/tires. I looked into Globe and they are reputable.
Could also search online. My previous two cars had HID standard so never looked at getting HID so not much help in that area. I did upgrade wheels/tires from our old C class.
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