A few years ago I built a pair of 4430s after landing a pair of the correct bass drivers effectively for free. There are accurate plans on the Lansing Heritage site. Theres a thread about the build here
https://www.hifiwigwam.com/forum/topic/132714-jbl-4430-clones/
Anyway, afew years later I'm still using them and they sound better than ever.
How good? Well, I own various tannoy classics - Reds, Golds and Silvers in various cabinets, and prefer these. These would be a lot of speaker for the price offered, though to get the most from them you might want to use some Radian diaphragms and modify the crossover to bypass the active/passive switch.