Alright ive got a guy here at home with a GXP that would like me to change his plugs and wires as well as his thermostat. I was curious as to how much of a b**** this job may be? And if any of you have any tips before i go into this as i'm not too familiar with the ls4. And where is the thermostat located on these? Is it right on top like an l67 or is it hidden under the intake manifold or something tricky like that? Thanks for any help an tips you can give me. A