The Crosswind already uses a Di engine. The older Isuzu 2.8 is quieter. That's why most newer Di and CRDi engines live under plastic shrouds to contain the noise.

If a closely similar Di and pre-chamber engine were both bench tested, chances are the Di engine will be noisier as there is no pre-chamber to contain the noise of the explosion. However, more modern encapsulation, insulation, and acoustic technology has allowed Di engines to have similar if not quieter noise levels than conventional pre-chamber engines.