Hey Guys,
I just picked up a 2004 Cayenne Turbo and had a quick question about the TPMS system. When I scroll through the menu system it shows the ability read TPMS sensors, but since the wheels were aftermarket i'm guessing the previous owners did not put the sensors in the wheels.

My question is this, If I want to add sensors to the car to integrate with my current TPMS system, what are the best sensors for the money and how do they link to the factory system? I'm seen some for $150 for the entire set up to $450 for the entire set. Any money spent on this pig, won't be spent on the 911 so I am trying to be budget conscious. (please spare the PCAR budget conscious jokes )

Thanks in advance!

PS ; will they work on 22" wheels? I thought I read somewhere that 22's are a problem.