I have seen that style intake before and your maf sensor code could be from a bad seal where the sensor plugs into the intake tube. You can try reseating it, possibly add an o-ring. Honestly I would probably put the SVT air box back on and consider it a lesson learned in cheap parts. I tried a cheap intake on my Zetec at first and ended up with a Volant and it was worth the money spent.
Look around the forums and SVT section a bit.