I have a very loud whistle coming from the back of my car. It gets louder on acceleration and reduces when I am on the clutch. I just got aftermarket stripes put on the trunk but that was all I had done to it. I don't think it would have an effect.

 

i would make sure the antenna base is completly secure and the trunk is fully latched, are the stripes going around the hatch?

also it could be something completly coincidence

windows not completly shut, piece of trim hanging