The connector. Provided that you get the correct actual sensor (but only a Bosch sensor, not the generic stuff from the auto parts store), there's nothing wrong with buying a universal and re-using the connector from your old sensor.

ok, thank you, thats what I needed to hear

I was planning on splicing the old connector too the cheapo $30 O2 sensor anyways.

Just wanted to make sure the cheapo $30 sensor will work on a 1997 Porsche Boxster.