If I make one, I'm going to do a solid model and everything so I can get everything cut with a laser or waterjet and then TIG'd. I figure if I go through the effort, I should probably make a small production run if they work well. Pace Products in the UK makes a cool hybrid air to air / air to water for WRXs, it's pretty cool too. I'm going to put my own spin on that concept, but keep it air to water. I don't like the heatsoak of the air to air topmount, I just think it's a bad idea.