I've read a fair amount of discussion on the forum regarding both running the tires at a higher PSI for better mileage and also upgrading to better tires. In my manual, it mentions that the tires have to be equipped with tire pressure warning valves and transmitters for the low tire pressure alarm to work properly and also if the PSI is more than 7.3 PSI higher than standard, the alarm will not work correctly. Were/what are these valves and transmitters and how would they be transferred to new tires? Also, has the higher PSI created any false alarms? Toyota is even recommending that flat tires have to be repaired by Toyota or run the risk of the valve or transmitter not working properly. One last thing, the manual also says that the ID code has to be registered?