I do NOT regard buying DIY kits off the shelf from a company selling those kits and building it according to the pre-designed and fabricated components such as crossover a DIY project. Those projects are just replication of the existing design that the company has fabricated or copied from the manufacturer (hopefully does not trigger infringement of intellectual property). The DIYers do not really design anything. That is not a hobby but "killing time" only. I am not sure what kind of fullfilment or satisfaction they got out of it. The DIY company even tells you that, if you change the front panel of the speaker
(for example), you need to change the design of crossover and they cannot help.
BTW, I do consider cloning a specific speaker shape/design/pattern a infringement of interllectual property, big time. Imagine how cloning Wilson Audio speakers of worth more than 20k, 30k and above possibly damages company's business.