$700 is a litte much for a stock Si engine (D16A6), but u can probably get a ZC which is DOHC and 22HP more for not too much more than $700, or a SOHC VTEC (D16Z6/D16Y8/JDM B15B) for that matter... U can get an exhaust now, and then always swap later... Im not sure how thick the piping is on your stock exhaust tho... Im not sure if mine is stock or not, but that muffler went on like stock so I guess its the stock diameter of an Si... The muffler cost me $189 with shipping from Arizona to Louisiana...