I kind of like the speakers if I could get them to sound a little better.
I'm not quite sure how to repond to that. Kind of like this would be a pretty good meal if it didn't taste so bad.
I'm sure that modifying the crossover and/or replacing the drivers will change how they sound. Predicting the results will be tough. It should be cheap enough to play around with the crossovers so I would start there, but buying quality drivers to play around with might get expensive.
Bear in mind that whatever modifications you make will probably kill the resale value. It sounds like you have the inclanation so if you have the resources and skills it might be better to build your own from the ground up and then sell what you have.