Looking for info/opinions on installing onboard air and upgrading to an air horn. Anyone done this and have pics and tips? I'm thinking of going with an ARB twin compressor, installing an air tank, and going with a semi horn (since train horns are illegal). I don't plan on honking at everybody but some folks are real idiots when they drive (and text) and the factory horn is pathetic. Also, I need the oba for inflating tires so I don't want to go with a horn kit. Any insight appreciated.