Ok so let me start off my review saying the customer service is top notch here at SE motors. I noted in my purchase notes that I heard about the other 2 customers that had purchased these headers and complained about the flex hose leaking. Knowing this was an issue they now are coming with straight pipe 304 stainless steel where the flex hose used to be. No leaks on my MY 14 2.0 Base Impreza with the SP2 exhaust system is sounds very nice and looks very sleek. Definitely adds some HP but without a pro tune or without tuning it myself using my OpenPort2.0 I cannot truly say how much it is. If I had to guess I'd say over 10hp due to it being a nice set of headers. Your car will run rich afr wise with both these installed so I'd highly recommend a tune to maximize the gains. I'll be shopping here in the future for exhaust systems. Serious bang for your buck!