Two things I'd be concerned with by removing the hood insulation. One is the noise factor, a lot of that material acts as a sound dampener. But I like a loud engine & exhaust, so I don't care about that. More importantly, though, you may notice paint discoloration on your hood because the insulation isn't there to keep the heat away. I've seen this on several older cars, maybe it isn't a problem with new paint jobs. Then again, with clearcoat, maybe it's a bigger concern; I don't know. Also, removing the insulation doesn't really cool down your engine bay, at least not enough to make any noticable difference (not in my experience, anyway. Other people may say differently). IMO, the biggest factor in lowering your engine bay temperature is to coat your headers. I have Jet Hot coated Edelbrocks on my Caprice & they lowered the temp 15-20 degrees depending on how long the car has been running. That can make an honest difference in intake temperature.