With velocity chamber to minimize turbulance inside the pipe. Stainless steel high polished for stylish look. Fit perfectly without any modification. Estimate increase in HP ~ 15 to 20.  NO EGT bung.

Fits: GDA04 (04 WRX), GDA02 (02 to 03 Impreza Sedan), GDBC (04 STI), GGA (02+ Wagon)