Be sure of buying a FUNCTIONAL cold air system.
In this, episode 126 of PowerTec 10, DV follows on questionable cold air systems and so called high performance filtration from episode 106. Using a 2.3 EcoBoost Mustang as an example both cold air filter boxes and filters are flow tested to establish the need for a usually expensive aftermarket system. Watch this episode as it could well save some $300 - $500 on an aftermarket system that can be outperformed by the PowerTec 10 do-it-yourself design discussed here which will set you back at most about $80!