Just installed one of these on my 08 EGC. Funny thing, it was a direct replacement for my stock horn. Granted it doesn't fit under the cow bell and is somewhat ugly, but man this thing is LOUD. Gonna wake up them cagers in Orlando with this thing. One question, it came with a 30 amp relay. Not real savvy with electrical stuff. I plugged it into the existing wiring, and she works just fine. I would like to use the stock/factory wiring that was on the old horn, do I need to install this 30 amp relay??