Land Rover Repair: Gems or Bosch. Which is the better engine, engine management system, gas mileage

Question
What is the difference between the GEMS & the Bosch engine? Which is better? Thank you for your time.

Answer
GEMS is the engine management system that was used from 1995 to the middle of the 1999 model year.  BOSCH is the engine management system that replaced it mid year in 1999.

BOSCH trucks get slightly better gas mileage and have slightly more power.  The BOSCH system is generally viewed as more desireable.