+1 to cutting all mids.
http://www.ibanez.com/bass/series.aspx?s=k5
Huh, it looks like they just remade the early 2000s era Soundgears in a different color with a different headstock. My old five string has the same pickups and electronics, but they discontinued that right after I bought mine...
Anyway, you'll probably want an EQ pedal OR find a light distortion that completely sucks your mids. I'd go with the EH Metal Muff, because it has the three band EQ and might let you get light enough distortion wise to just sound like a bass through a cranked amp. Actually, you should try the Pocket Metal Muff as well just to see if the mid cut switch is enough for you. I've played both and they were a lot of fun to mess around on.
Best of luck.