sgt brad, I went with the top speed header back set up on my 2000 2.7. (headers, cat deletes and mufflers). I am in the process of lengthening the O2 wiring.
From my experience with Bosche O2's a 5 wire is a wide band unit while a 4 wire is not. I've used the 5 wire in some of the turbo cars I've built in the past in order to log the air fuel to tune AEM and other stand alone ecu's with.
Bosche also make "universal" 4 wire O2's that come with a good length of wire that I might give a try. You just connect your plug to the new O2 wire with the supplied splice connector. I've used them in everything from BMW's to Honda's with great success.
Partsgeek.com has them for the up and down stream for most years boxsters. Prices are $44-$64.
