Most are probably aware that the upper guide pin on the rear calipers likes to work itself out and should be checked, but have any had it actually shear? We've had it happen three times now in a year on one car. My other car hasn't had any issues (though it has Xidas on it which deal with the rumbles much better). It is the right (passenger) rear and we're a counter-clockwise track, so it is the one that takes the brunt of the rumble strips. The car has a stock motor (+ header and SM intake), 190K+ mile original bushings on it and the RR upright bushing is definitely shot, cheap eBay Chinese coilovers, stock sway bars. The caliper was replaced at the end of last year (though ran a 6 hour enduro and ~4 race weekends), the bracket does't look bent (via holding it up to another bracket). New bushings are in the works, and hopefully a better suspension if I can get my codrivers to go for it.