Your fuel pressure is too high. With the FPR vacuum line disconnected you should have 37psi base pressure (43psi if Auto trans). So even if the injectors were stock sized, that could contribute to running rich at wide open throttle. If you have larger injectors and no way to tune or compensate for them, you are definitely running rich. However, your narrowband gauge won't be able to tell you this. When your engine is under boost, the ECU richens up the A/F ratio significantly. There are quite a few reasons for this, but regardless your narrowband is going to read "rich" whether your running the optimal A/F ratio or not. This is why many consider them completely useless. You need an actual air to fuel ratio (such as 10.9:1) to make any rational changes.
So I would start by lowering the fuel pressure to the correct point. Then find out exactly what injectors you have, what type of MAF you have, etc. Without knowing these things, your really just running blind. Then get a wideband and look into a tuning system of some kind (such as DSMLink, Ostrich, even SAFC).