The synthetic switch question is when you're ready. Different people have different opinions, usually very strong. I change with the first oil change which was 3000 miles.

Superchips says "no" additional modifications need to be made at all!!! That being said, I wouldn't do it without gauges just because I want to see what's going on, but I can also say, I haven't been able to get the EGT's into a danger zone yet. 1100 or so is the hottest I've been able to get it. But then, SC is not one of the hottest tunes out there either; it's safe and somewhat conservative I think. Even so, guys in SD's are running in the mid 14's in the quarter with SC.

 

I get 18.53 MPG in my stock 2000 PSD with 64000 miles on it. As the engine ages the MPG's seem to get better?!