http://www.ricwood.com/dtm_v6_25.html
That's been quite extensively developed, if it's even based on the same engine. No cam belt, for a start. Not a surprise as a setup like the standard one with great long flappy runs of spring-tensioned rubber belt would make a bit of a mess at 12K RPM IMHO. That lump has certainly had some cash thrown at it. Web site confused me a bit because you click on the GM engine and it morphs into a Ferrari V12. I'm off to the garage to try it on my Y32SE.

Its all about torque with the 2.2 DTi, bhp means nothing really.
Other way round. BHP is what it's all about. Different torque delivery will make an engine feel fast (or slow) but BHP (or power to weight as KW rightly points out) and having a gearbox that suits the torque delivery is what matters in turning out performance.
Put another way: A 2.2DTi has 280Nm of torque. So does a 3.2 V6 (near as makes no odds). Do we need a drag race?
Kevin