Originally Posted by gomer_110

While I can't give you a link to one, I've seen inserts that go in the end of the muffler that are designed to reduce the sound.

Also the turndown idea works pretty well. Even just pointing the turn down at the ground can make a big difference. Not sure the diameter of the tomei muffler tip but I've commonly seen autoxers use a HVAC duct elbow as a turn down with just a hose clamp holding it on.