Here's my insight on this as I'm thinkin of getting my 92, w/OEM gps screwing windshield tint, tinted w/ 3M tint. 3M is pretty much the only way to go.
You shouldn't need much, if any, heat from gun to get the tint to fit/stick good.
I've tinted in a previous life. But I sure don't wanna do my svx's rear window
Find a good shop as w/ any gearhead stuff. Which can be tuff.
Check your state tint law,
Clean'em REALLY good before you take them in, including edges and corners.
Blow off w/ compressed air, if possible.