I read that stock 440 injectors are capable of i think 350hp max, maybe a little. Given you are running stock fuel system (pump, fpr, afm, injectors) you will need to run low boost for sure or i believe you will hit fuel cut.
+10000 on reading up on how to tune prior to install. Btw what dm kit are you getting? the upgraded ct, or the 60-1 with mani and such? Any ic upgrades? without the supporting mods you are better off to save money until you can get everything you need plus paying someone to tune for you.
Really no point in turbo upgrade if you cant run more than stock psi imo. i would go with the injectors pump and afm first. and tune around that.