u lose

i did search this with lots of different answers. about an hour of reading.

My car: 94 non-cali FD manuel

mods: new reman with 1700 miles on it.
stock fuel system but all new parts
apexi gt spec exhaust
apexi hard pipe intakes
greddy 2-row FMIC

other notes:
boost gauge
water temp gauge
greddy bov

Stock ECU

Question:
I would like to clean up the engine bay and get rid of my annoying mooing sound for good. as far as i understand it now, i need a block off plate kit, and some type of high flow cat, and a smaller belt. now the last tim i did this i had a PFC. can this be done safely on the stock ecu? and what is the real truth behind the lumpy vs. not lump idle people are talking about without the air pump.

Any other advantages or disadvantages to removing the AP?

BTW.. i don't have emissions where i am due to the fact that i don't drive it over 5k a year.

thanks for the help