Hi
I'm Chuck from SF, California.
I've been building crossovers for many years.
In this new age of DSP and inexpensive bClass-D amplifiers, I have found the best results with active crossovers and multi-amping.
Other than pro-gear, an inexpensive many manychoice I've found is the XKitz (not affiliated)3-way LR 24db/octave crossover kits and also available premade. They use plug-in frequency modules for simple choice of crossover points.
For amps, Ive had good luck with Ice Power and Sure amps.
For passive crossover design I recommend reading a lot and LDC by Dickson is a good starting point.
Ciao