Chevron Techron concentrate, always pick up 2 bottles when it's on sale 2 for one. Run it once a year with 6.5 oz of MMO/16Gal every fill up, my 04 stratus with the 2.7 is getting better gas mileage now at 115,000 miles than it did at 50,000 when I bought it. ~29mpg at 75mph, car is only rated at 25mpg so I can live with that. The best proof I had was when I started getting rough idling and a bog/hesitation around 85k, I researched a bit and went with the techron, by the end of the tank my mileage had improved significantly since I drive the same route every week and the rough idle/hesitation completely gone. Car has never run better and it's kept me a happy customer. Whatever works for you is what's best in my opinion.