Need I say more? Quality metal, looks great on the 124. I'm really not sure why it didn't come this way from the factory! I'd recommend this to be one of your first aesthetic upgrades!
As far as signal, I would say a small loss but nothing significant. Works just fine in town. Only when I get out into the hills, etc I tend to lose my favorite stations. Personally; the trade off for the looks is worth a slight degrade in antenna/FM performance!