I can tell you what it took: buying a car with a wimpy stereo and no bluetooth support. I have an '08 Honda S2000 CR – awesome car, pretty crappy stereo. The worst thing was the inability to use my cell phone without hands – hands free is important with a manual gearbox.
I wish I could provide details for what I put in my car, but I honestly don't remember – and most of it is hidden (maybe, I can find my receipts). The head unit is a Pioneer Premier and the amp and speakers are all JL Audio, including a neat 10” stealth sub which tucks away in my unused spare tire tool well (the CR doesn't come with a spare – I have a pump and a plug kit instead). The amp is where the spare would otherwise go. I wouldn't call it audiophile level, but the car doesn't exactly have a quiet cockpit either – it's a sports car, after all.
The important thing to me is that I can hear it and it actually has halfway decent bass. I don't have to handle my phone in order to use it – just touch a button on the head unit to answer, or to dial via voice command. As long as the top is on the car or I'm not ripping down the highway, I can actually converse without a problem. It also features iPod support, which is what I'm using as a source. It was probably silly to dump $3K into a system for a car like this, but I can't deny that I'm a bit insane.
My previous car was a Cadillac STS, which had an OEM (Delco/Bose) system as well as a very quiet cabin. That sounded terrific, but when my car isn't moving, my current system is better. As with audio in the home, the room is critical. The large, well insulated cabin of the STS provided a great environment for audio enjoyment. The tiny, noisy cockpit of my CR has a completely different purpose – the enjoyment of spirited driving.
