With ply cabinets, I use small finishing nails or brads to tack the spkr together until the glue dries. Screws are really unnecessary. The important thing is accurate, tight fit. For MDF, the screws and glue may be better.

I glue all sides and front and rear... all access is done through the woofer hole.

To glue the crossover components... E6000 glue, Alene's 7800, or Goop Automotive Adhesive and Sealant. These are all the same, which are "SBR" adhesives. That is Styrene Butadyene Rubber. It dries clear, and is very, very slightly flexible. It bonds dissimilar materials very well. I have not had a coil come loose yet with this stuff.

Predrill all holes. The screws will hole well without breaking up the materal around it, and thus, actually a better hold.

Woofers MUST have T-nuts behind them. Screwing into the baffle only is OK, but only with light drivers. Heavy pro drivers as used for Pi Spkrs, wood screws only will not do.