I swapped my hologens for the Litronics a year ago. No problems to date.
The Litronics will not adjust up/down when driving, but will move up 5 degrees when you switch to high beams.
It is not plug & play. You have to do some wiring, but it's very simple.
Suncoast Porsche had the best price for the lights.
http://e-partssales.com/Merchant2/merchant.mvc?
Here's the web site with installation instructions.
http://www.realtime.net/~rentner/Porsche/Litronics/InstallingLights_Starting.html
Good Luck.