Owners agree the head bolts themselves are trivially cheap; the expense is labor to get to them. Estimates in the threads range from a shop quote of about $5K inclusive of parts (exclusive of cams/cam gear) down to roughly $610 in parts and about six hours of labor at dealer rates of $125-$300/hour. …
Head-bolt remedy: cheap bolts, expensive labor
Mercedes-Benz R63 AMG (W251) · ownership