Regular will work but it won't save any money. I accidentally put regular in my car once and it ran OK because the computer adjusted to it by retarding the ignition. I had less power and mileage went down enough to kill any savings. 10.5 : 1 compression is way too much for regular. IF you drove your SRT real easy and below 2,500 RPM, the SRT would have run better on regular since it has lower compression.