The procedure sounds interesting.

I would also suggest a separating panel, between the filter and the engine. Ducting cold air helps, but at high speeds, hot engine air from all kinds of places ends up at the K&N. Using real time temp sensors, I found that depending on the speed , underhood air turbulance increases / decreases. Higher speed doesnt mean more fresh air. It means more underhood turbulance which distributes hot air from headers , radiator, oil fliter case etc. If you just remove the airbox and stick a PowerFlow type k&N, you will suck warm air. I was warned about that and my measurements proved the hot air warning.

More ducting helps, but a separating panel eliminates the problem. Here's what I did:

Go to Home Depot and get a roll (I think its like 10 feet long, 12" wide) self-adhesive aluminum A/D duct insulation. Basically this is a flexible sheet of aluminum with sticky foam on one side.

Since one side of the sheet has soft aluminum and the other sticky hard foam, we could attach two sheets (foam to foam sides) and voila, we have an insulating panel that looks metalic and is not tacky (no flames from Conqours judges and trailer-Queen owners please).

Find out how long the separating panel will be and cut TWICE that lenght of the
aluminum sheet (you can use sciscors). Fold the sheet in half so the sticky sides glue to each other and you have a sheet with aluminum on both sides.

Use tire wraps to attach the sheet to the edges of the radiaror and wherever you feel
appropriate. This setup is very secure, I went over 130mph with the setup on and the panel didnt move a bit.

Thats it. If you dont like it, take off and you lost $10.

My thermometer readings loved it. It makes ALL the difference in the wolrd at least temperature wise. From 0mph (hot day / DC traffic) to 130mph the intake air temp (sensor placed in front of AMS) is equal to ambient.

Power wise, my butt dyno is not calibrated and consequently I cannot claim any performance gains.

Regards
Vlasis
95 Avus Blau M3