There are various options available, so check the link above for pricing. You can get 15 guage or 18 guage coils, your choice of standard or premium resistors and an assortment of brands of high grade poly caps. Below is a photo of the version with Auricaps, Mills resistors and 15 guage coils.
The picture actually shows me drawing an outline to cut out a gasket. I like to mount the crossover boards directly to an inside panel to prevent vibration, and put liberal daubs of silicon under the coils to cushion them too. Use a hole punch on the gasket for mounting holes. Sandwich the gasket between the crossover and bottom or back of the box and snug it down. Easy as Pi!