When you find the car you want, take to a reputable independent shop for a thorough inspection. This can be done even if the car you are interested in is hundreds of miles away. Just set up an appointment with a good shop and let them know that the inspection is "for you" and will be paid for "by you." This ensures that the shop is working in your best interest and not that of the seller.
An honest seller should have no problem with taking the car to the shop of your choice in the area.
Me - '98 M3/4 (manual)
Estoril on black Nappa, UUC clutch stop, de-baffled airbox, Pilot Sports
Wife - '04 Discovery II