Does any one know how to get those damn water spots off the bonnet stripes? And how to keep them off for good?

And a side question... My aero grils are fading and i do not know how to keep them black and shiny?

 

The vinyl stripes are a bit more fragile than paintwork, but I would recommend most of the same treatments. I would start with a very fine paint polish (paintwork cleanser). A cleaner wax should also remove these spots. I think that I would avoid the vinegar wash approaches of waterspot removal. Claybar may also work, but be sure to use extra lube.

As with any recommendation on-line, I would suggest testing whatever product you want to try in an out of the way area before doing the entire thing. Some of the colored areas on vinyl decals are printed on using an ink-jet printer. Some of the solvents will smear the ink.

Once you get the spots off, the key is prevention. I would apply several coats of a sealant to the entire car (Zaino or Klasse). This should help reduce the permanence of the water spots.