Retrofitting a simplified version of TMPS is fairly easy. If unshure, grab the genuine sensors (you'll get them for about £100), let a workshop fit them into your wheels (maybe when you already need to change them) for about £10 per wheel. Then grab somebody who install the ConversMod onto your cluster and you're done. The Mod prevents the cluster from complaining about the missing antennas and also give the possibility to assign wheelpositions by applying different pressures to them and store it. I use this since many years and where very comfortable with it.
No need to retrofit the antennas. They are just for comfort. The receiver for the TPMS-sensors is built into any car, it is the same receiving your keyfob signals.
(oh, btw: i am that "German guy" mentioned above ;-)
Edited by go4it, 15 December 2020 - 04:28 PM.