What are you considering a rebuild?

The M103 typically does not need an "engine rebuild". Usually just a head refresh and seals.
The bottom end is pretty bulletproof.

__________________
2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k