What happens when the eng bay heats up??? My understanding that the warmer the air going into the eng the less HP and performance.

I tried a simlar set up years ago on my 328 BMW. Didn't work so good.

Set up cold air induction on my 330CI. Big improvement. The differance was in the way the cold air induction kept the filter compartment cooler than the lest of the eng bay and the piping to get as much air from the outside of the car as possible. There was a small air restriction because of the way BM keeps everything pretty tight in the eng bay and front assembly, but manage to get more air to it than stock and the K&N cone was less restrictive.