Front Bank STFT Maxed out Rich-Suggestions

[NOMIEZVR4]

Stock Injectors, Walbro 255 Hotwired Flash ECU

EVOscan is showing front bank is running lean as the Short Term Fuel Trim is +12.5 maxed out. The car has NO boost leaks. New Fuel Filter. Brand new Denso Oxygen Sensor as well on the front bank. o2 Activity is normal as the sensor voltages are fluctuating as they should. New Spark Plug Wires(NGK) and Spark Plugs (NGK Copper R5811a). Car occasionally throws a p0300 I believe because of the Short Trim being maxed out. I would really like to resolve this issue before throwing the big injectors back in. I am aware that it could be a partially faulty injector that could be causing this but just want to make sure I rule out all other possibilities before swapping parts and tunes.

Just for reference, Mid is +5
On the rear bank, Short is +2 and Mid is +6
All help appreciated.