As far as I know tint is a secondary offence, they can't pull you over for it, unless if they are AMAZINGLY anal. And I know you said my 20 seems a tad bit dark, and 35 on your car will look just as dark (being that it's a coupe and has dark interior). And I HAD 35 before it's just after a while the sun started bugging me on the inside.
And lastly, keep in mind that no matter how good of a tint you get done it will still fade a slight bit. My 35% was perfect at first, but after it faded slightly, I wanted darker, hence my move to 20%