I just had new SO2s mounted and balanced and the well-meaning technician replaced the valve stems at the same time (no they didn't charge me for them). My concern is that they are about 50% longer than the OEM valve stems, and they may flex outward when the wheel spins at high speed, contributing to valve stem fatigue and possible failure. The car sees about 120 mph on the track for short periods, and rarely more than 80 mph sustained on the highway for any length of time. Is this a worry? TIA