Stock horsepower on an Evo IX is 286.

 

But it runs a 12.89 stock and a VIII will run 13.4 if it is a 05 if it is a 03/04 it will run 13.8ish
basically
2006 IX 12.89
2005 RS 13.1
2005 MR 13.3
2005 VIII 13.4
2004 VIII 13.8
2003 VIII 13.8

the IX runs a bigger compressor housing 20.5 PSI which the 03/04s run 19 and taper to 17 at 5000RPMs and the MIVEC head adds help down low