F/R brake balance is generally not an issue with the stock calipers and master cylinders a car came with. The Altima MC and Maxima rear calipers were just another stock set up for the NX2000's sold in Europe as NX100. That means Nissan's engineers already figured out the brake bias saving you lots of testing. Just swap in the parts (all of them!) and enjoy.
The problem comes with partial conversions. Like if you convert to the Altima master cylinder without going to the Maxima rears. If you do that the f/r bias will get thrown off because the Altima line pressures are different from the various B13 master cylinders. The pressures are posted somewhere.
I know many owners change over to the Altima mc because it gives a nice high pedal. But it throws the bias to the front. Where it really shows up is at the track. Under threshold braking conditions your car will be less stable, front rotor temperatures will be higher, front pad/rotor wear will increase, and stopping distances will lengthen.
On the street, I doubt you'll see a difference other than a higher pedal and shorter travel making modulation a bit more skillful. On the other hand I know trackers using only the Altima MC (no other changes) who say they are happy with it.
I learned otherwise. It was only when I finally converted my NX2000 (with stock ad22 fronts and Altima MC) to the Maxima SE calipers that I realized just how much the f/r bias had been off with just the Altima MC.
The change to the full system as Nissan intended, transformed the car under braking. There was an improvement in feel, modulation and stability. I had messed it up by just throwing an Altima MC at it. Finally finishing the job brought back what had been one of the great things about the car.
Yes, the NX2000 had one of the best brake packages you could find on a car with economy roots. And the brakes contributed to making the NX2000 a legend in the SCCA SSB class during in the early 90's.
Even more interesting, Greg Amy's ITA SCCA national runoff winning NX2000 of just a few years back, was on stock NX ad22 front and rear calipers (not the larger Maxima ones). That should tell you something about the effectiveness of stock brake hardware your NX2000 came with. These were and still are powerful and correctly proportioned brakes. And a pad change can still keep you playing in the game when you want to go tracking and time trialing.
But if it's esthetics and you just don't like those wimpy looking little rear rotors looking up at you through the spokes, Nissan gave you the Euro package described in this thread and others: Altima master cylinder, Maxima SE calipers and 10" rotors (same size as the fronts!) to bring things into visual balance.
And the nice thing is changing it over will not cost you and arm and leg either.
Phil