IJ40 + 8048. We used to use 8508... but the past 10 or so rolls have been really cloudy. Nothing like making a beautiful print, then laminating it and seeing blur marks/clouds everywhere. We find 8048 to be better.
IJ 35 will shrink... Sure, it's rated 5 years... But thats unprinted, unwarranted time line. IJ35 on a vehicle that sits in the hot sun... Not only will it look like crap after a year, but it'll be brutal to remove.
IJ-40 is great for non curves, and after 5 years if/when it starts to fade... You can remove it easily. 180 is better, but if it's a flatish surface, not worth the extra cost.
I'd never use IJ35 on a vehicle... Even if it were to only last a month, removal time would negate any savings from stepping up to IJ40, even if your not removing it.. The customer would likely remember what a pain in the ass it is and not use you for it again.