Just back from BHP car festival and ran the 2004 2.5 M54 Z on it. So she's nearly 20 years of age and should have left the her birth factory @ 189bhp and 181nm of torque (I think that's right) she ran 210bhp and 248nm @ peak engine speed of 7236rpm.so the open intake and straight pipe and tune have gathered back all her power and more. Bearing in mind it was 29 degrees ambient air temperature I think that pretty decent for her. Sounded epic as well!!!!