It's about 15 to 20 cents between grades..87 to 89 to 91/93. With a 22gal tank, the difference between mid & prem is at least $3 per tank (.15 x 20gal), and it'd be $6 per tank comparing regular to premium. Not arguing there may be quality/additive benefits to simply going premium.
It also got excellent mpg’s, sometimes above 30 on road trips. However the repairs and reliability were getting to be too much. The DEF tank or sensors failed multiple times, including once while on a road trip. The car put a message up of ‘will not restart in 300 miles’, which is really comforting when you’re 1,000 miles from home. lb9uoAG.