They did switch on E90's, as of 03/07 SOP, now all 3er sedans and coupes have TPMS which uses an in-tire sensor to monitor actual pressure. If you use a product like "slime" or the goop that is part of the mobility kit, you will likely have to replace the sensor, which runs anywhere between $35 and $50. The hole in the sensor will get plugged up. Not sure if it can be cleaned up afterwards, but its doubtful.
2008 E90 328i - Sparkling Graphite/Terra/Dark Burl, 6MT, Sport, Premuim, Fold-down seats, iPod/USB(6FL). M-Sport Steering Wheel, ZHP M-Sport Shift knob, Euro fog lights. Euro Split Armrest