brake pad and rotor

hi there.
i just bought a x5 2001 3.0
but i have to change the brake pads and rotors on the rear area...
1. my question is, is it ok to change 1 axle only? the rear axle, since i dont see any prob in the front brakes???
i know x5 is an awd vehicle, do i need to change the 4 break pads and rotors or can i just change the rear?

2. and also front brakes are regular stock. can i use the slotted rotors for the rear and stock pads and rotors in front?

im a diy guy...and this is my first bmw...but i do know a thing or two re simple maiantance work..but for bmw, no clue as i am fairly new to it....

Yes it's fine to so one axle. As long as it is one axle and not one wheel on that axle.
Dealerships do that anyway. (Found that out long ago) Had to go back a month later because I got the fronts done and they said nothing about the backs and about a month later I returned after I got the message for the backs... damn bmw
You can get whatever rotors drilled, slotted, don't matter as long as you 'bed' them in correctly after install.
The thing is though, you would want the (performance) rotor up front because that's where most of the heat is developed and the slots 'or holes' make it easier for the heat and pressure to escape. So the slotted rotors would be more beneficial to be up front if you were to only get a set on one axle. The X is heavy so if you do a lot of aggressive driving those fronts would wear faster.

thank you thank you boramkiv...this is very very helpful for me...maybe in a month i will change the front ones with the same rotors...
cause as off now the back is squeaking...thanks again..
is that your x5? nice rims...