You will need the engine, engine mount parts from a 190E 2.6, wiring harness for a 190E 2.6, engine ECU for a 190e 2.6, radiator and associated cooling parts (they are unique on a W201 with a 6 cylinder vs 4 cylinder, there is essentially zero clearance between the fan and radiator even with the special radiator in the 6 cylinder W201), and the ignition module for the 6 cylinder. Really only reasonable if you have a donor car or a DEEP wallet.