get any decent desi exhaust or buy one from hpr,maxpower or other mod shops in ur city. get 3" custom piping made from any 'silencer wala'. search on net for header specifications and pics of headers for 4afe engine. Show them to the silencer wala and he will make them for u
total cost= 3000(exhaust)+2000(piping)+4000(headers)=9000
this is just an estimate. Actual may vary according to how you bargain and whether u know ur stuff or not but more or less it the actual cost should be around it