Are they dark gray solid or the gray/black two tone? You're in for a lot of work...that also means changing glove box and lower dash panels...carpet too I guess. The tan is cooler.

If you go for it, be very careful removing the rear upper side panels. They get very brittle with age. You might want to get some extra snap connectors for the door panels - usually, a few break in the process.

If your dash wood needs refinishing, you might try to find a set on ebay or somewhere and refinish them in advance, then, when you change the interior, it will take little more work to swap them out.

Best of luck!
Patrick