These looked rubbish in Fiorano at the last round of the ENS a few weeks ago. The stock OS's wiped the floor with them. Even the Picco WC engines were quicker and I haven't got a lot of time for Picco engines.
I did expect more from the XRD engines (especially as the people behind it came from screaming sirio heritage) but very disappointing to be honest. You can't beat the stock OS's or modified Novarossis. I call BS on that RPM claim as well
maybe off load but no way in practice.