VH-XXX: There are lots of 2 litre diesel cars and commercial vehicles out there pumping out figures higher than that.
But they're not running at 75% power day in day out and not going to 100% power every time they start moving.
The 1.7 litre Thierlerts were unreliable at 135 HP. That's why they stated fitting 2.0 litre 135 HP variants. The 2.0 litre ones at 155 HP are approaching the same power to cc ratio as the 1.7 litre ones were at 135 HP. I'd say it's reasonable to presume reliability will suffer for the 155 HP 2.0 litre variants. So far as I know the 2.0 litre 155 HP version hasn't been used in any numbers yet.
The gear boxes are another issue. Gearboxes on engines of less than 9 cylinders producing much more than 100 HP have generally never been all that successful/reliable.
No doubt about it diesel or JetA1 is the way to be heading, but no one has yet built a successful diesel GA piston engine, much less one that is based on an automotive engine. By successful I mean one that can compare to the likes of the typical Lycoming or Continental for cost, power to weight and reliability/TBO.