[solo the lad]

I'm considering swapping my dif (06 n52 3.0 manual) to something with a higher final drive for a little more neck breaking action, and so that I can spend more in gas. I believe I have the 3.46, and im thinking I want to go up to 3.91 (those can be sourced from the e46's right?). So I would like to know:

what ratio did u swap to?
where did u source your dif from?
is the difference actually noticeable?
will I still lose races?

thanks.