I will chip in here as I have had the IMS Guardian installed for 2 years now. No warnings or any problem yet. I test it before I start each time. To me it is worth it as I don't worry about the IMS anymore.
I change the oil every 5k miles with Mobil 1 synthetic and check for metal in the filter.
I pay attention to changing fluids frequently - Porsche antifreeze etc. Will change brake fluid this spring. Enjoy your car. Drive it safely. Life is for living!
