turbo 6 bangers post here

I am starting to plan my draw through turbo setup and I had a very good friend offer to build me a sheet metal intake manifold. He is going to cut it out on his laser jet machine so it will be done right. I have chosen to make it out of steel instead aluminum for cost reasons. My question is there any downside to using a sheet metal intake over a normal cast intake? I know it would be easier to run a cast intake but my buddy is doing it for material cost only. My design is equall length straight runners off the head and then into a triangle shaped plenum that would feed into the intake piping. I will try to get pictures of my design on here soon. Another concern I have is with doing a draw through setup is there anything I need to do special inside the intake manifold for fuel/air flow?