No decent shop will do the single row chain b/c no-one in the know will stand behind such piss poor engineering. Those single row chains will break in less than 40k and no decent shop will risk their reputation to save you money. I know there are people who just love the 107 but after 10 years of working on benz's.... you couldn't give me that car. If you're gonna drive a quirky expensive roadster with jack for interior space, it should at least have some muscle under the hood. 5.0 maybe, 5.6 sure....3.8 why bother?