If anyone is REALLY interested in finding out what effect if any a commonly used cetane improver (2-Ethylhexyl Nitrate), found in such products as PowerService, has on engine durability/longevity when combined with ULSD, you can buy SAE International's test paper on the subject.
A 1000-hour test was conducted to determine the durability effects of 2-ethylhexyl nitrate (2-EHN) cetane improver on heavy duty diesel engines. Two identical 1993 DDC Series 60 engines were run side-by-side on a severe duty cycle. Both were fueled with a commercial low sulfur fuel. The fuel in one engine was treated with 7500 ppm of 2-EHN cetane improver. At the end of the test, engine wear and deposit comparisons were made to determine the effect of high cetane improver treat rates on engine durability.