The 2.8 is pretty rubbish and like tabs says it rarely makes anywhere near the quoted 150bhp. The 2.9 is much better and usually does make 150 or even a bit more, even on tired engines. Check out the couple of rolling road sessions in the magazines featuring xr4x4s and the 2.9s always did well.

Even so, its still nowhere near as good as a 24v.