Correct. I'll know actual figures next week.

I gotta stop flooring it

 

Ahhh yes.. no yellow box installed at all yet. Just put in the 4.57's.. and thats all. But I really doubt everyone on the freeway is coasting at 90, so I'm assuming my speed is off for sure

 

Do the ~500rpms or so make a differnce in gas mileage when cruising at 80mph?

 

I believe your gas mileage would be affected in general as you are reving higher throughout the powerband.

 

Yes, it will. For example, I went to 4.44s. This is about an 8% change in gearing and hence, an 8% increase in cruising rpm in top gear. My fuel economy dropped by 10% on the highway, but a small bit of that was due to having a supercharger. I say "small" because at highway speeds, the supercharger is barely boosting.

 

I can still get 31 mpg on the interstate if I drive with the top up and set the cruise control for 75 or so.