as im sure most of us that have Aux enabled, also have "hiss" enabled. this IS the answer. sure you could make your own GLI, but whatever you make, probably wouldnt give you a whopping 1.3 dB gain! yeah, thats right, were talkin a HUGE jump here! lol seriously tho, this has got to be the easiest answer/fix for the grounding issue. when i recieved it, i turned to my Aux port, with nothing playing, blasted the volume to get the most hiss possible, plugged this inline, and nothing. dead silence... the way it should be. probably the best 25 bucks ive spent on this car. this weekend ill do a write up on the MP3 player im using too..
http://www.crutchfield.com/S-LxEG1myoeM4/cgi-bin/ProdView.asp?g=181150&I=127SNI135&search=loop
http://www.crutchfield.com/S-LxEG1myoeM4/cgi-bin/ProdView.asp?g=181150&I=127SNI135&search=loop