Can a six cylinder be easily installed in a 190E that had a four cylinder in it before?

Yes, it is possible to install a six-cylinder engine in a Mercedes-Benz 190E that originally had a four-cylinder engine, but it may require significant modifications. Key considerations include the engine mounts, transmission compatibility, and the wiring harness. Additionally, upgrading the cooling system and exhaust may be necessary to accommodate the more powerful engine. Overall, while it's feasible, the process involves a fair amount of work and expertise.