I see your post says Airrex. I hope your not thinking that Airrex is the same as Airforce. IT is not the same . Airrex is better quality product over AirForce.
IF you like pricing for Airrex I would just keep it all airrex you will run into less issues rather than mix matching the systems. Hit up site vendor www.stillen.com
they are an Airrex dealer in SO cal and install center