The preparation you do to your Mustang prior to body and paint will depend on the level of restoration that you are after. If you just want fresh paint on a daily driver then you can probably drop it off at the paint shop and let them go at it, leaving any disassembly and removal of parts up to the body shop.
If you’re doing any level of restoration such as replacing weather stripping and seals, moldings, emblems and electrical items like turn signals, headlamps and brake lamps then you may want to remove most of the parts yourself to save a few dollars that the body shop would have charged you for removing these items.
In the case of Project Playboy it’s all about removing everything all the way down to the spot welds, with a few exceptions. A complete restoration requires the complete disassembly and anything that I leave bolted to the car will eventually be removed at the body shop (See section 2. Mustang Disassembly).
Aside from removing all the nuts, bolts and screws and cleaning the goo from the windshields and pulling all the weather stripping and plugs; I also tagged and photo graphed all of the problem areas that needed attention that could be addressed at the body shop.
This gives the body men an opportunity to see what concerns you may have and if you photographed it it serves as a great reference as the work moves forward.
never assume that the body shop will automatically know what to repair, for all they know that hole in your floor belongs there.
There are a few parts that I leave on the car that will later be removed by the body shop. The remaining parts include the rear axle and leaf spring, upper and lower control arms and spindles and the doors. The suspensions components remain so the Mustang can be loaded onto a trailer and moved around the shop. The doors go to the body shop mounted to the car so the body men can get an idea of how the doors are mounted before they remove them; the back edge of the doors sit about 1/8 inch high at the rear after all of the components have been removed, they should be remounted to this location before the Mustang is painted.