Yes, the PSI range depends on the load range. I have LT load range E Toyo AT3s and the max PSI is 80PSI for the highest load on HD trucks. I run low 40s on the Toyos to match the stock P metric Pirelli tire load at 35.
Straight from Toyo...
I have this "issue" too and it drives me nuts. Even worse on my wife's Expedition. 2PM, not a cloud in the sky and my headlights come on from the shadow of my own roof if the sun is to the rear. Dash dims then I can barely read anything. Crap design.
Drag goes up dramatically as speeds go over 60mph. At 70+ I wonder if you may be able to get a little more MPG running a lower gear that doesn't need to get in boost as much. NA engines are going to downshift, but these turbo engines seem to be programmed to just pour on the boost instead.
Pressing M first will just enable manual shifting.
Pressing the -/+ alone just acts like a gear limiter, it will still shift up and down the range that you allow like normal.
While in Drive, press only the - button on the shifter. Each press will lower the highest gear allowed. + to raise them back up. The gear numbers will disappear on the dash gauge as you change it. It will reset to normal if you shift out of drive.
No idea on specifics, just adding my observations but the 3.5L seems to be programmed to increase boost rather than down shift the transmission whenever possible. The low RPM and high torque load is what leads to the engine lugging/shuddering IMO. I lock out 10th gear until I'm over 60mph and...
I've got the AT3s in 275/65/20 on my truck with a leveling kit. Zero rub. Pretty much echo the comments above. They've finally started making a little noise at 14k miles but I still consider them to be very quiet.
I'm another in the camp of the EB sounds like poo so I'm not in favor of it being louder. I'll be happy with the some turbo whistle and quiet stock exhaust.
As for the exhaust power/torque I think it is given that anytime you see increased HP gains on the top end advertised a side effect is...
Is that an F80 I spy? Good taste, I've got an '18.
I put 275/65/20 Open Country AT3s on my truck. Probably could've gone a hair bigger but didn't want any rubbing issues and wasn't much data to go on back in January.
LTs usually have more plys so more resistance to punctures and I would rather have the height than the width. Not sure how much the weight vs width penalty would be on fuel mileage, they might cancel out.
Personally, I live on a dirt road and spend as much time off pavement as on so I didn't...
From what I've noticed, my DRLs stay on from the time I unlock or approach the vehicle until I turn it off and lock it. Headlight dial in the auto position. ETA maybe the behavior is different for the 502A lights