Most of the changes had to do with durability! & of course the 2.3 was turned into a 2.5. Larger oil pump, double row timing chain, & better cams were some of the changes.
Not much that can be retro-fitted w/o spending big $$$$.
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)