Insight on heat protection please

[TDot]

So I got this computer in the car now. One day the temps in NY got up to 102, so in my trunk it hit 117 and caused my computer to shut down. Because of this Im thinking to line my trunk with heat shielding. Should reduce the temps by 30-40%(claims by manufacturers), I'll be good with 15-20%. This got me thinking about the rest of the car with this heat and the price of gas and AC. What if I lined the rest of the car...doors, backseat, whatever else with this stuff to help keep the heat out while parked (along with my winshield screen), and the AC in so I can use less.

My problem with this idea and my question is, because of the windows (although tinted) letting the sunlight/heat in, wont the heat now be trapped in the cabin? The trunk I'm not worried about because I figure if every crevis is covered the heat will just be kept out.

From what I understand the soundproofing stuff can carry the same heat shielding properties, so if you don't have specific info on this and you've soundproofed your car, how has the soundproofing material affected the heat of the summer for you?

[06M4.5]

The only way to keep the heat #'s down would be by venting, crack the windows or keep the sunroof on tilt. keep the rear armrest door open so the trunk can also get some air. The heat on the glass is the main problem (with or without tint)

More important is the heat under the hood, it's unreal how hot my M45 gets. I wish I could get some kind of vent on the hood without it looking ugly.

[TDot]

I'm glad you mentioned how hot the engine gets because I thought I was going crazy thinking my engine is way too hot. I've never had a car with an engine that got this hot. You can feel it he walked by the front wheel or standing by the front door and that isn't even after a long hard run .

[06M4.5]

I do open my hood for a few mins after long rides just to let some heat out.

[pedsemdoc]

The only way to keep the heat #'s down would be by venting, crack the windows or keep the sunroof on tilt. keep the rear armrest door open so the trunk can also get some air. The heat on the glass is the main problem (with or without tint)

More important is the heat under the hood, it's unreal how hot my M45 gets. I wish I could get some kind of vent on the hood without it looking ugly.

Interestingly enough--they've studied whether cracking your windows helps keep down the heat--for about an hour it decreases the rate of temperature rise, but after that there is no difference in temp. We see young kids left in cars brought to the ED, so that's why I know that little factoid. you're better off parking in the shade if you have the luxury of a parking garage.