Well, I don't have TRD springs, I'm running Progress springs (although I had read somewhere Progress makes the xD springs for TRD) and I've noticed my left front sits almost 1/2" lower than my right front on level ground. I've had my springs on the 'D for about a year. I just assumed the difference was caused by the extra weight of the driver on the left side (in my case, about 300 lbs, lol!), causing the left spring to settle further...