So over the weekend I had several upgrades planned. I changed out the spark plugs (see pic of how bad they were) and then installed a stage 2 jet chip. So far, I am absolutely loving the chip! Very easy to install. It was the 2nd plug for me (orange plug) and snapped right in. It really helps the Nitro especially at highway speeds. The shift points are much better than stock. I'm still running unleaded fuel (87/89) and the OEM thermostat. I do plan on trying either mid-grade or premium gas just to see if it changes any. I read some of the other posts that says it sometimes runs better on unleaded 87/89 so I want to test it out. So far $200 well spent!!