I am thinking of swaping my 273's out of for some 373's with the gears only make a difference out of the hole or will they pull harder in all gears up to top speed? Oh and should I go with 373's with my setup with nitrous?

 

Either 3.42s or 3.73s. It depends on how many rpms your turning now at the finish line.

 

They will increase performance at all speeds for the most part. There are some exceptions, but with your setup 3.73's seem to be a good choice.

 

You want to avoide running out of RPM's and being forced to shift to fifth through the traps, this means you have too much gear.

 

Read the sig I have an a4

 

They should help all over. 3.73's are good for auto cars.