DIY Speakers

https://solen.ca/  has a large supply of speaker parts.

I would check also Humble Homemade Hifi and HiFi Collective.

Madisound for woofers, midrange, tweeters and crossover parts.

You can also look at Sonic Craft, VH Audio and Parts Connexion (partsconnexion.com) for additional crossover part options which Madisound does not carry.

Why does everyone hammer on parts express? I’ve purchased many replacement drivers from them and found no problem with anything I bought there.If there was a problem they were real quick to take it back. Somebody must be buying there because the place is huge and has one of the best inventories in the United States and Canada.

I don't think the OP really "hammered" on Parts Express.  I think he's just looking for the higher end of DIY speaker parts.  I have purchased several things from Parts Express and they are an excellent company.  Their "Dayton" series of drivers are very excellent for the money and sound damn good for what you are paying.  They are not the highest resolution parts, but they definitely don't sound bad.  I have used other types of drivers from Parts Express when I need a specific type of driver.  They do carry Janzen caps which are also good as well as Solen caps.  They also have an excellent level of subwoofers and full range drivers.

But they don't carry stuff like Seas, Accuton, ScanSpeak, Mundorf, etc.