Mr. Heissmann is a nice guy. But with all due respect, well earned, DIY cannot compete with KEF R3 (non meta) bought new or pre-owned for instance. The slight emphasis in treble is easily tamed with using the quite pretty grille - or an equalizer. Dissemble, repaint, put together again, measure, enjoy.I'm looking for something up to the $1000 range for drivers and crossover.
If DIY I would go for other things like 12" bass/mid plus horn etc., parts from the scrapyard or overstock ond so forth. The knowledge to be invested with an own design is crucial, but exactly that make the savings, me thinks.