Should you have your Mustang blasted? I would say yes, others will say no; it all depends on your depth of restoration. If you want to expose any possible problems that may be hiding under the old paint job or road grime on the undercarriage media blasting is the way to go, but be prepared for those surprises; what may look like a small rust problem on the floor pan can turn out to be a complete floor pan replacement.
If you are pretty confident that the Mustang you have selected for restoration is in really solid shape you may decide not to go the rout of media blasting but I would recommend that you at least have the exterior of the vehicle blasted and leave the undercarriage alone; this will save the body shop a lot of hours sanding and exposing any problems and will leave your undercarriage and interior untouched.
Project Playboy got the full media blast treatment; interior, exterior and undercarriage and there were a couple of surprises with the floor pan which was to being replaced; the front floor to firewall extensions had some minor rust issues and would be replaced.
The driver door also had more problems than I was willing to let slide into the body work phase; besides showing more damaged now that its been blasted, it also has rusted out areas on the inside of the shell.
Now I will need to start looking for a good used door, I’m not to sure if I am ready to venture into a reproduction door shell just yet.