Been using CSW Model6's in my home gym for the past year. While they were good enough for the $25 I paid for them, they have their weaknesses and roll off hard at 100hz.
I've had some Coustic Design Reference 7" mids sitting around for about a decade. Despite being car audio mids, they're old enough that they actually have more home audio TS parameters. Figured I'd put them to use and gain some more DIY experience at the same time.
Trying to ball on a budget here as these speakers aren't uber important, more of a learning experience than anything. Decided to go with a Woofer Assisted Wideband arrangement for a couple reasons. First I wasn't sure of the usable high FR of the mid but I'm sure with the ancient technology involved it's going to be unimpressively low. Second I was trying to really pinch pennies here and getting a ($10-15) cheap tweeter that will play low enough to mate with these modbass was unlikely. The Vifa TC9, however, is only like $7 and will easily play down near 100hz if desired.