I don't find the SPL solid AL rear diff bushings to be t0 loud...Yes, the rear diff drivetrain noise will sound like woo, woo, woo every ~0.5" @ ~40+ mph (my350Z also supports this claim); inherent in teh rotation of the ring gear in the rear diff. It's not too loud though! I have a gutted rear Nterior trim, Ncluding no d0Nut. The strate piped Xhaust w/bullet mufflers drowns out the noise....Of course I don't daily drive my Z34, but for a "for fun" weekend car these bushings R "teh shizer!" I highly recommend 'em to anyone looking to cure the dreaded wheel hop...
