I have always liked this hood mod. Looks like a great chance for aero to meet style, IMO. Would it effect engine cooling/temperatures?
Wood the "crack" on the side be a place where some rubber/plastic could be inserted to maintain a surface for the air to travel over?
This modification is done for people the have Individual throttle bodies on there car (to receive fresh air), for turbo cars (to reduce under hood temps), and by people that just think it looks cool. So yes, it can affect under hood temps. but whatever you use to fill the gaps on the sides, I'm sure you could use to seal the back of the hood as well.