[Ssopus]

Long time lurker, first reply...
Identifying your budget and what kind of sound you are trying to achieve (spl or sq) are good starting points. You’re not confined to the normal equipment selection that you see in typical installs. It’s not bad advice to spend a good portion of your budget on sound deadening. I’ve heard some pretty good systems that were put together with somewhat inexpensive components get great results. A lot of variables control the end result...most important being the install.

Do the research...consider impedance and sensitivity and how well they preform off axis when choosing drivers...setting gains properly...if using a DSP read everything you can about level adjustments, setting filters, experimenting with crossover points and time alignment. Education and knowledge are the best tools that benefit you during a diy install. Sound is not subjective, sound is consistent, however the perception of sound is subjective. If you have the opportunity to demo before purchase I highly recommend it, although I rarely get the chance to.

If you have the budget for Audio Developemet W800 Neo’s underseat (powered by discreet channels)... I recommend them. A very sound (pun intended) mid bass selection. They take a custom adapter (which is an easy diy if you have a router) but well worth the effort. Mounting a good quality tweet in the sails is also an added plus. Fiberglass resin and body filler are your friends. If you want to save yourself some time, select a DSP like the MiniDSP c-dsp Dirac unit. It’s capable of room correction which (via microphone) auto sets your levels for you (oversimplified).

You can spend as little or as much as you want to achieve a result. An automobile is a terrible environment for audio, but with the right install you can make an inexpensive system sound good and a higher dollar system sound superb. It’s a rabbit hole that once you fall into its very hard to crawl back out of. A hole that, after 30 years, I continue to tumble down.