With out sounding rude, you have this all backwards.
Not knowing how much boost your running and turning it up from stock is totally silly. Turn it down all the way so you are just running stock wastegate pressure for now, then go buy a boost gauge first!
And you will need a wideband afr kit to tune the afr, dont bother trying with the stock narrowband its not linear where you need it to tune, its only good for saying if you above or below 14.7 for the ecu to cycle afr at cruise, and the ecu will adjust the fuel trims here anyway, so if you o2 sensor is working there is nothing to be gained at cruise.
Dont bother messing around with an an egr, afr is much more usefull,, resposnds quicker and they are cheap nowdays. If you won't first spend less than 300 on a wideband dont try to tune the car untill you do. Or you'll be buying a new motor.
