You want highs?? You could add tweeters but to get the full highs out of the music go aftermarket. I'd recommend either Infinity's, Pioneers, JBL's, MBQuarts', or Alpines. There are many more out there but these are just some of the best IMO.
2007 Ford F150 Supercrew sold
2010 fully loaded Ford Fusion
2002 Mustang GT being built in garage.....stay tuned!!!!