Hella Horn Wiring Harness 02-14 WRX, 04-14 STI - GrimmSpeed Best harness out there. I bought the Perrin hella horns kit and the bracket but had no idea that I needed a wiring harness, I'm so glad that Grimmspeed had the harness by its self for me to get. I have no idea how to electrical stuff but this harness made it super easy. Thanks Grimmspeed! Subimods V4 Hella Horn Harness Kit Most Subaru Models Subimods V4 Hella Horn Harness Kit - 4 is the new 2 . Many customers do not realize that when you purchase a set of Hella Supertone Horns you will only receive a relay and some brief instructions on how the horns should be connected, some customers aren’t fully equipped to handle such a task others just don’t have the time to deal with making their own Wiring Harness from scratch.