My fuel gauge also trips out when switching to a different tune. Initially it drops to beyond empty, then it's back to normal soon enough.
I think I tried to start and restart immediately once, to see if that'd fix it. I don't believe it did. Maybe I had to log a few miles before starting the engine again to get the needle right.
The battery disconnect fixes my clock too but the question is WHY??? It seems like if they know the bug exists they could fix it. Aren't they the smart guys?
I recently added 5Star tune to my 2013 V10 EB50 4x4. While the change wasn't dramatic I did notice a slight seat of the pants gain in power around town. I always noticed a lot of down shifting on the slightest inclines on the hwy in stock form, but the van seems to hold gears better now. For my year van, the only tunes available are daily/tow based on octane. So far I'm just using the 87 tune bc gas prices are up and filing a 46 gal tank stings enough at these prices. We'll see if economy is improved any as we take or normal trips over the summer but considering our average of 8-9mpg it will take some time to recoup the cost of the tuner assuming we get even .5 mpg better. But that's not why I bought it as I was looking for improved driveability over economy. I mean....it is V10 camper van.
I never saw any increase in mileage with my 5 Star tune but I do think my 2013 V10 drives better with it. It is much better in the hills and shifts are crisper. I like the 91 octane tune best but with the high gas prices now 87 is what I’m currently using.
I bought a tuner from 5-Star for my 5.4 E350 a few months ago and they said they would not ship even a blank tuner to my Ohio address without sending them a copy of my Ohio registration. That resulted in a refund. There's more to the story, but I'm extremely bummed out to say the least.