Ask about balancing abilities: do they use dynamic high-speed balancing for long shafts, phased assemblies

https://research-wiki.win/index.php/Choosing_a_Custom_Driveline_Shop:_Evaluation,_Balance,_Custom_U_Bolts,_and_Repair_Considerations_for_Work_Trucks

Ask about stabilizing capabilities: do they provide vibrant high-speed balancing for long shafts, phased assemblies, and on-vehicle diagnostics to minimize vibration, sound, and early part wear.