I just purchased a 2008 SC430 with 58K miles. I have a subwoofer buzzing and probably needs replacement. I found a replacement on Lexuspartsnow.com. $450. Does anyone have the procedure to remove the rear seats to get to the subwoofer and replace. I don't want to pay Lexus $1200 to replace. I added a GTA Iphone connection to the CD/Cassette stereo and it works good with stock head unit. If any one has diagram or have replaced their subwoofer it would be helpful.