We sort of have a class A (the Axis is really a C in A clothing) but it does have the V-10 (although with the smaller and lighter chassis we typically get 9 mpg).
This is our 3rd V-10 we've had though. Our first two were in pickups and my last one (an F-350) I got a tune from these guys:
Got a 2006-2015 V10 RV ? - 5 Star Tuning
There service is 2nd to none and the guys at
Ford Trucks - swear by them. On our F-350 I gained about 1 mpg but a lot more seat of the pants oomfh.
Note: Not paid by them, just a happy customer.
I kept my SCT tuner so that I may get a tune for our Axis.