s14 notch top drivability problems

[sloth240]

I have a 98 240sx and a 98 notchtop sr with vtc. the car pulls nice until around 4500-5000 rpm then it feels like it hits a wall. I have 550 cc injectors and z32 maf and i have an "NA" tuned ecu for it. I have had lots of experience with red tops but none with s14 sr. It is idling around 13.1 afr and under full boost it is around 10-1 afr. it is super rich.

does this sound like a vtc problem, injector problem or ecu problem? also can i put chips from a tuned s13 ecu into the s14 ecu?