I agree the exhaust is critical to engine location when building mounts. I install ALL accessories that will be used. This eliminates getting everything fitted and built only to find out that the exhaust would have fit IF the engine was sitting a quarter inch to the side. If you take precise measurements (I use 3D computer models from GM) you'll see that it is common that GM and most manufacturers offset a RWD engine to the passenger side for clearance even on late model vehicles.
