Combustion temperature directly relates to "power stroke efficiency".

Getting the same combustion temperatures off of a super lean "30% less fuel" injector charge sprayed into a supercompressed red hot air charge means that all that "extra air" sorta puts you into the realm of turbos and superchargers combustion-wise.

This could be a performance upper if they were able to put it into larger displacement engines, but in a small 1800 cc straight four it will still be a mild performance, high gas mileage vehicle.

Danger is that bearing and rod loads go way up in diesel type compression vehicles -- so you'd be better to buy from someone who has already built diesels that had a rep for being long lasting.