LOL that Tornado is crap, I remember someone testing it a while back and in reality it hurt MPG and performance.

They say it adomizes the fuel...

How can it when the fuel is injected just above the valves WAYYY behined the tornado.

They say it helps the airflow out. By the time it goes threw the intake elbow and threw the intake and threw the head its not going to matter.... Don't waste you money

4.10's and MPG don't mix even with a 6 speed its not all that great untill you get in 6th but its not like a 3.42 or something.

Im going to say 18mpg all around maybe 20.
With 4.10's in an auto it will suck.

The LT4 kit sucks... lot better stuff out there. I don't think they make it anymore either.
If you want a good all around gear for a daily in a A4 go 3.42's..
Don't go flomaster...

For MPG do things like.... tune up, synthetic fluids, maybe an aluminum driveshaft.... start small also.... you will lean more and save a lot of money.

Ram air does not do all that much. In a LT1 car they have proved it does not do much at least with the SS hoods and all.