Car Audio Questions - 64 Dart 270

I’m looking at JL 6*9 3-Way Speakers for the two speakers on the package tray, and the speaker in the dash.

I’ve found kickpanels on eBay that fit 5 1/4” speakers such as these JL C2’s or these JL C5’s, and kickpanels from Retrosound that fit 4*6 speakers like these Rockfords.

Beyond that, I know I want a sub to get good bass, so I’m thinking a sealed 12” or 2 placed behind the backseat in the trunk. Not sure what sub though. I’m also unsure about what a good amp(s) and crossovers to run to make sure it all sounds best.

Any advice appreciated.

Look online for audio forums and start reading up on things in your price range. Lots of good experience online along with things to avoid.