I don't think the exhaust will get any louder. In my opinion, I would go with just the two perforated-pipe method where the exhaust is cut open through the top and two of the four perforated pipes are either covered up or replaced with just regular pipe. Put back together and start it up. It'll cost a couple hundred dollars (paid $250) and a couple hours (2-3) but once you listen to it it's much much better than stock but not too loud until you step on it.
You won't hear the exhaust with normal city or highway driving (no drone at all).