I was under the impression that the Audi part AU4A0905849B was the newer version of the switch and it was compatiable on the 97 -2004.5 MY Boxsters.
If you have two did you try to install the other one with battery off, could have shorted it out during install if you had the battery connected the first time.
On Suncost (where I bought mine) it worked fine.
Ignition Switch:Porsche Parts & Porsche Accessories - Wholesale Porsche Parts & Tequipment - Cayman Panamera Cayenn
By the way what part of Houston are you located at? Might have to get the other Houston area Boxsters together before it get's too hot for top down driving.
