Are you able to use regular gas in this car or do you have to use premium?

91 min is recommended, but you can use 87 octane but have reduced performance. Maybe use 89 to split it?

Premium is required because this vehicle has a high compression engine. To save money I'd suggest using regular with an octane booster at each fill up. STP Octane Booster is a good product. I used it for years in my 1970 Pontiac Catalina to stop it from dieseling. It really does work. Hope that helps! Jim