Off with the stripe...Use a "eraser wheel" tool to get it off...thats how we do it at work.(auto body)
For the painted on guys...wet sand lightly with 2000grit...and then rubbing compound and polishing compound and wax...Id try laquer thinner 1st though.
I like pinstripes, but most people don't. However, if you were going to leave it, I would extend it to the front bumper as it doesn't look right stopping at the end of the fender.