mines got down pipe decat, K&N panel filter and 5" jap style H&S Back box. And did 242 with a boost problem so should be about 248-250, with the rest decatted and remap Prosport said 300bhp. With a STi panel filter and uprated fuel pump.
unfortunatley good performance comes with good sound, no need for radios wind down the windows and its the best headache i ever get.
if you fully decat you defo need a remap.