It isn't normally neccessary to change the motor as well,done loads now and the old motor has always worked fine once it's screwed onto a new regulator,and one slow window is normally a sign that very soon you'll also be learning how to put a new regulator in.
And if you do this job yourself,make sure you have an M8 ZXN or triple square bit to undo the two bolts that hold the lock mechanism to the door,these are NOT Torx bolts and if you try to undo them with a Torx bit you will damage the head of the bolt,especially if it's never been undone before.
Chris.

DLS Iridium 8.3,Vibe Space 12 V3,Vibe Bass 4,Vibe Stereo 2,Vibe Stereo 4,17in RS4 reps + 50% tints.
Coming soon...Image Dynamics CD2 horn loaded compression drivers (oooh get me!)