I mounted my Yaesu FTM-150 control head on the dash above the screen and the main unit under the rear seat next to the battery. I connected directly to the battery.
I mounted an FTM-150R in Maverick. The main unit is under the back seat and the head is mounted above the entertainment screen. I used Bullet Point mounts for that. I can send some photos later, if you are still interested.
From RigPix: The Ft 991a draws a peak of 23A at 13.8 V (+- 15%). Cigarette sockets are rated to 10A max.
https://www.rigpix.com/yaesu/ft991a.htm
I would run a line directly to the vehicle battery. Make sure to tap it in after the BMC modules on the battery. Or run the rig with lower than 100W...
I worked at Ford many years ago, they never stopped the line for any problem. Missing part document it and keep moving, part doesn't fit, document and keep the line moving. They have a rework lot that cars with issues go to get fixed later. "Paint it blue and ship it thru."