After some long searching I have finally become the owner of an 2018 S6. The car has a blown motor (stage 3 build) that I knew when I purchased it. My plan is to replace the engine with a used one and I would like recommendations as to what items or systems need attention on this motor when replacing? Timing Chains, fuel injectors, valve seals, ?? I’m new to this engine platform but not new to engine rebuilding.