I'd appreciate any tips on adjusting valves you guys may have. My 450 had 2 valves just slightly tight on the intake side. So I went about re-shimming. It's just like any other project, one trip to the dealer will not get it done. e.g. the factory shim on one valve was a 182 so according to the manual I rounded did the math and installed a 175 shim but then it was too lose. The 180 shim did the trick. I was amazed that it could possibly be that sensitive. It really makes my wonder about the tolerances of the shims I bought from the dealer. My advice is to buy a couple of shims in the direction you need to shim so as to not have to return to the dealer. I was very unsure about the difficulty of the project not having done it before but it really isn't a big deal at all. I think it's very cool that I have a well used '03 and this is the first time.