I would more than highly suggest you get a tune. With your mods, mainly full catless DP, your car is running higher boost than stock, and creating much more heat. The whole purpose of a tune is to add more fuel to cool down the combustion chamber. If you do not, you will lean out, and eventually blow your motor. It is bery dangerous to run our cars, or any car, with heavy modifications and no tune.
Do not trust the prosport boost gauge. My AP proves that my prosport is incredibly off! Mine was 4-6 psi off. You need step colder plugs right away! That's the cause of your misfire, and could solve all your problems. Also I would get an AP, or standback. I would suggest AP. Very easy, datalogging, and cobb just broke through the load cap barrier. So it can do EVERYTHING now. A tune with your setup is needed. Tuning my car was by far the best mod I have done.