I'd have to agree with adam on his lengthy statement... just from what I"ve witnessed out here... I did the pulley route.. but did use supporting mods (which is why my car still runs) but I am sending my head out soon (whenever I get it off the damn spare motor) to get a full port and polish and upgraded valvetrain... that should free up some serious horsies.

 

The M62 is already at its limits with a 2.8 pulley IMO. A swap to a more efficient form of FI is the best solution to more power. Of coarse it will need the supporting mods and the proper monitoring equipment.