UV film sounds like a good option for lowering cabin temps:

http://petrolicious.com/does-window-tint-ever-belong-on-classic-cars

Living in the desert, I've tinted windows on the family sedan, but not the Z.  Tinting does keep the interior much cooler, plus I like the look.  For the Z, I prefer a rear window louver.  Tint film has the ability to pull the rear glass defroster grid off the glass which is a major downside for me.  If you go with tint film, check local laws on which windows and how dark for tinting.  Laws and tint shops often have different opinions.

Dennis

+1 on the rear window louver.  It's a must for me here in GA, especially since my AC isn't working yet.  Plus I've never liked the way window tint "blurs" the occupants exterior view. Just my opinion.

 

Good point about damaging the rear defroster, even though UV film is not supposed to interfere with its operation. Regarding tint laws, this stuff is clear so they claim it even can be applied to the windshield. Distortion is a consideration, though.

Yep I'm here to tell ya, it will destroy the rear defrost. I lived in Vegas for 17 years and tinted my windows. The thing is, eventually you'll have to remove it due to blistering and discoloring. There is no way to remove the film from the back glass without damaging the delicate defrost grid. So if you like and or have the louvers I would use them and maybe tint the side windows. It was the most miserable experience I've had yet with my Z, removing the old tint. My back glass had 2 layers. I think that's how they did it 20+ years ago. The darker the tint the more layers you got. Thinking about it, my tint was on for 24 years before I removed it. Had to heat it to remove the tint and most of the adhesive and then wait for the glass to cool so I could scrape the glass free of the residue. Not fun! 

I'd like to hear you-all's experiences with the optical quality after tint film once applied to glass with the usual (and well earned) "patina" of scratches, pittings, etc.  The defroster grids are raised off the glass, does this cause obvious line-distortions or is it pretty good? Side windows? How do the scratches and dings look, ie are they hidden or accentuated? 

I'm trying to decide if this something I want to do this summer.

I'm still in the fence with the Louvers versus tint. Might do both here in alberta

I recently removed all the side window tint that was put on by the owner before me.  Didn't like it, too dark.  The factory tint looks just right to me.

Left the hatch window tint on to try to preserve the new carpet.