manifold makes no difference as its the throttle body that it joins to.
yes it could fit directly onto the airbox, where my BMC CDA is positioned is the same place the hole from the airbox was, so it would fit yes...
but...
you would need to talk with EarlofBarnet and confirm with him that it would fit exactly where the origional airbox was, as I was the ginuea pig I had to alter the elbows + alu pipe etc etc....
not what most want to be doing,
the origional origional fitted like this, and could not fit onto the origional position of the inlet pipe to connect to the airbox...
I dont know what EarlofBarnet's plans are, but the origional pipe design in the above picture wouldnt fit, so hopefully he would have sorted all the problems out before selling it to other people
Hope this helps matey