I would just go with a trusted professional such as the CMF Aluminum airbox. That is if you are trying to get the most out of your blaster, otherwise don't bother. Anyways here's there website,http://www.cfmracing.com
I wouldnt tell him dont bother. If the guy has some tools and can fab his own stuff dont discourage. Ive seen pics. of a guy who made his own aluminum airbox and it looked sick and worked great according to him.