I know 18 seems high but if you had to follow me anywhere you would get it. I only take the tach over 2000 on the highway and even use 6th on level ground if I'm around 50. Takes me forever to get up to 65 but I'm tired of it and want to drive again and I will give up a few mpg for that. When I do decide to drive like everyone else in NJ my mpg goes down to around 16 but I still don't have the pep that I want.
JT

 

If you aren't spinning a minimum 1800rpms at cruise speed, you are running inefficiently. The sweet spot for efficiency is 1800-2000 rpm with stock wheels and a couple hundred higher if you are rolling on 35s. Rolling around at 1500 rpms isn't gaining you efficiency and in fact it bears a cost.

Chrysler didn't come up with the gear ratio/tire size options they offer on a whim. They all target that sweet spot of around 2,000 rpm for a 65mph highway cruise. More rotational weight and they start tweaking their number upwards. That certainly might not offer people the performance they want, but it makes for a nice number to put on the window sticker.

 

I "hate" the 5.13's with that set up because it was too much gear for the 35's. It was was terrible on the highway, gas mileage was worse on the highway than in town. I dont ever worry about mpg but it was rediculous to say the least. It was also annoying not being able to go over 70 on the highway without the engine screaming. I didnt like the all around performance of the regear, my 3.73s were way too low but the 5.13s were way too high. I know many dont agree and that is their opinion but if I was to regear with 35 and my 6 speed again I would go with the 4.56s. I am not saying this to start a heated debate I am just telling you how I feel personally.

 

I have an Auto with 35s and 5.13s, and 5.13s are a good fit for an AUTO... if I had a 6spd, I would definitely have gone with 4.88s.

As is, I'm only getting around 15-16 MPG on backroads... closer to 17-18 if I do all highway miles.