You’ll probably be disappointed with any autoeq that you try. It’s probably not worth choosing a dap based on if it has autoeq or not. A more important aspect is how easy it is for you to make adjustments yourself. A lot of new processors have phone apps, which is cool and convenient.

Subwoofers in small convertibles do not work unless you can fit them in the doors, between the seats, under the seats or in the passenger foot well. Typically, none of these are easy to do.

Your best bet is to make space for a dedicated 2-4” midrange and use your door location for the biggest mid bass driver you can squeeze in. This will require 6 channels of processing if you run active, which you should.

If you’re forced to keep the factory head unit as your sole source, you’ll definitely want some kind of oem integration processor.

The most budget friendly option is pretty much always going to be a DEH-80PRS however I don’t believe the 5+6(sub) channels can do high pass or band pass so that would be an issue for you in your subless scenario.