6250/.789/3.889 = 2036.88

2036.88/833 = 2.45 Assuming a 195/60/15 tire (just cause I don't want to go outside)

2.45*60 = 147

So you'd be doing 147 at the top of fifth with 195/60/15's.
With 18s you can do 157.
With 19s you can do 164.

 

Oh and the EUDM A4's top speed it 137.

 

bhj0887, your car is cannot do over 150, i have 80hp on you with a 2.8 trans and its not a walk in the park for me to do 150+.

 

i phrased that wrong. the transmission is capable of pulling the car to 150. My car is not going to do 150, unless it's on a big long straight downhill road.

The 2.8 trans isn't capable of more than 147 mph with 15's anyway at least not with a 6250 redline.

 

so if i get and exhuast, intake and chip will my top speed go up if the redline isnt changed?

 

nope, if you get bigger rims and a chip it will.

gear ratios will not change unless you physically change them.

Tire/wheel size obviously is a big factor. As you can see with 15s you can only do max 147, but with 19s its possible to do 164 (with a lot more than a chip/exhaust and intake).