Cooler intake manifold
............ Keeping your air & fuel cooler is always better, look at what adding Nitrous Oxide does when it cools the fuel being burned.
Sorry, but this statement is very misleading. Nitrous oxide actually takes part in the combustion reaction, it is not just cooling (although that is an added benefit at about -127°F). I forget the exact temp, but somewhere around 570°F the nitrous molecule breaks down, releasing the oxygen (i.e. when the air fuel mixture is compressed and lit). This oxygen can now take part in the combustion of fuel making it possible to burn more fuel; thus, you are able to make more power by burning more fuel.
I don't have time to correct all the weird stuff in this thread....but, to the OP, in the end, finding a way to get cooler air into the engine will give you a little more power, and the most bang for your buck. The cool can thing won't do much for you unless you are having vapor locking issues. The fuel needs to atomize, so heat is not a bad thing...however, you still want cooler air if possible because cooler air is more dense (not smaller as someone stated in this thread...I can explain that later if needed.)....in other words, you can fit more cold air in the same space.
High flow air filter, Good.
Cool air into carb, also Good.
