Rennline's tie downs are made of stainless steel and powder coated red, so they are easily visible to tow truck operators. Installation of tie downs will not affect alignment settings. All new hardware is included with the kit. Rennline's heavy/duty front tie downs attach to the strongest, forward most point of the 911's front suspension - the front of the a-arm. The tow hooks are bolted down by the same three large bolts that secure the front a-arm to the unibody, and they've been specifically designed as skid plates that will keep your 911 protected when traversing steep driveways or speed bumps. The mounting hole of the rear tie down measures 16.5mm. This is the same dimension as most shock mount bolts and several other suspension components. We will send the straight rear tie downs, but if you would like the 45° or 90° tie downs please call