Exhaust 16hp Power Max honda clone

[offroader]

Hey im trying to find a decent high flow exhaust pipe that i can bolt right to my 16hp power max honda clone. its basically a bored GX390 so im assumming anything that will fit that will work with this engine too. If anybody has a decent one new or used please let me know. ive already looked at roberson exhausts and i like them. just not sure if i want to spend that much on a piece of pipe really.... and i dont have a welder so i can't make my own. Thanks.