The "air" injectors you refer to are NOT AIR INJECTORS.
They are in fact CNG, compressed natural gas injectors, but do the job effectively as air injectors, although they were never designed as such by bosch.
Touted as "better" by those that use and sell them, makes you wonder what controlled the boost perfectly well before "air" injectors existed, if I was being cynical I'd think it was just another gimmick like closed loop!!
tabetha