Similar to above, look in the classifieds for cars being parted out. Just pick up the whole mirror assembly...

Now if you're real lucky, you can get a pre-98 assembly with heated mirrors.

Goin' Round Traffic Circles @ 50Km/h!!! \m/ -- 1998 E0 SVT #2119 of 6535 \m/ -- 2003 Sentra SE-R Spec V