Yeah I'd redo the wire from the board of you receiver. I did to mine, and its another way to colour code your car! so you would be better off getting some nice looking blue wire. If you dont want to touch the board just take it to a meeting and a heap of people should be able to help!
BTW I lengthen and shorten my AM antena wire all the time with no effect, as long as it is still going up in a tube. Is this not the case with FM?