I just built a component system myself using the 5.25" Audax Aerogel (40wrms):
and the Dayton ND20FA tweeter (15wrms):
I have also built a 2nd order linkwitz-riley crossover at 4200 hz. Now my question is...how many watts rms can a single channel handle? Do I just sum the wattages 40+15=55 watts/channel? I am guessing not, because the power is not equally distributed to the drivers due to the crossover. I am also using an amp which supplies 60wrms to each channel.