I have an 04 Impala SS. I swapped out my pulley and I installed a 3.4 inch pulley with new gator back belt. I also have a k&n intake. Now I heard that if you drop your pulley size you must get a 180 Degree Thermostat. Now my car comes stock with 180 stat and my oil temp and engine temp runs perfect. I don't see anything wrong? Does anyone know if I should get the stat or no? Then lastly spark plugs. They recommended me to get Autolite 103's...any suggestions of what I should do or even what else I should purchase...