GPS speed calculations are more accurate than a vehicle’s speedometer since it is not affected by the same inaccuracies, including the vehicle’s wheel size or drive ratios. It is dependent however on GPS satellite signal quality but with the use of moving average calculations any errors are minimal.
From here: https://www.facebook.com/corolla.infotainment?fref=ts
Mudflaps are now things of past and old fashioned. No JDM comes with mud flaps, if you notice.