I bought some big Cerwin Vega LS 15 speakers off Craigslist some time ago. I had a spare set of these bullet tweeters. For kicks I took out the CV tweeters and put the bullet super tweeters in. They're in for good now. I did no crossover change. I just had to change one wire terminal connector, a little cabinet refitting work, unsolder the supplied capacitors off the bullet tweeters, unplugged the CV tweeters and plugged in the bullets. The sound difference is huge. Gave new life to the CV speakers. The sound is balanced too. My smart audio friend says you can't just do stuff like that and get good results, but admitted it worked well in this case. CV has used bullet tweeters like these before.
I originally used some of these bullet tweeters in a set of monitors I built for kicks. The woofers are wired direct full range with no crossover to them and the bullet tweeters with their supplied capacitors for the highs. The monitors sound amazing! I tried other tweeters for the monitors, but the bullets sounded shockingly best.
I could see how the tweeter in yours could lack. You could try something like I did and have good results. I've messed with speakers for many years and have come up with some that sounded good without worrying about matching all the numbers up. Click on direct link below for tweeters.
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=270-102