The effed lift pump is the key to diesel in oil...maybe time for an electric lift pump, contact Genlightening he has some Carrier pumps awesome units, virtually eliminates air in system.....a little more money than the stocker but never have a issue again with diesel in oil.
Fix the issue of lift pump first before getting too excited about how runs...if it's starving the IP because the lift is leaking, you may find significant changes in driveability and starting by doing lift pump and maybe return lines and o rings too...Russ Type4 here sells good quality return line kits and o rings for a good price.
Those two things will affect overall performance significantly!