Custom upper engine mount forward shim

The introduction of the custom lower engine mount forward shim brings the bottom of the engine mount forward by 0.63mm. This is not very much at all, but I could see no harm in compensating for this by adding a corresponding shim at the upper engine mount. Doing this will ensure the mounting surface of the engine mount is as planar as originally designed. There is no need for this shim to be slipped between the firewall and the vertical stiffener, it can go directly under the engine mount. There are also no clearance issues, so it can just be a simple round washer made from 0.63mm sheet. These washers are made to an identical size as the feet of the engine mount.