electric seats - how difficult can it be ?!

[andrew]

i share "my" car with swmbo, and, since we're different heights, spend all my time adjusting the driver's seat ( and interior mirror, and steering wheel, but they're another story ), in particular, ratcheting it oh so slowly down...

so just how difficult would it be to install electric seat adjustment of at least the seat height ?

any pointers, links gratefully received