To the person asking why they advertise 23 mpg - I made a trip 100% highway and got 25 mpg with it on cruise control so yes it is possible.

That said, mixed daily driving I'm averaging 19-20 with a ton of red lines.

 

Its gotta be those 19's helping the MPG!!

Seriously, those are pretty good mpg numbers.

 

Based on previous posts on here, I am led to believe the series IIs in general get 1-2mpg less than the series I.

 

I'd believe that too. My Series I did get slightly better mpg. I've been tracking my mpg's since my first tank...and the first tank was an eye opener - 14 mpg lol.

Been going up ever since and lined out around 19.4 mpg with the occasional tank getting over 20 with more highway miles on it.


One thing to note that driving 70 mph vs 80+ mph on the highway does make a huge difference in fuel efficiency. Probably more than 15% but then again 70 is just plain boring in an RX-8.

 

On the Nebraska Highways *Speed limit of 60...* I got 28 MPG. I was happy.