Better than any short-range FM transmitter, you can get a hardwired Bluetooth FM modulator that plugs directly into the antenna port in the back of the radio head unit, then your stock antenna cable plugs into the modulator. The modulator picks up your Bluetooth and taps the output signal directly into the physical antenna circuit at one of (usually) two selectable frequencies on the radio dial; here's an eBay search for them . There's also similar, older-style FM modulators without Bluetooth, just an aux-in jack; these were commonly used to tap aftermarket CD changers into stock factory radios back in the day. IMO these would be preferable if your audio source (e.g. phone) has an aux-out/line-out or headphone jack. Anywhere you can eliminate a wireless signal in favor of a hardwired connection for audio, the better. Finally, if your stock head unit has a cassette player, there's also rechargeable dummy cassettes with Bluetooth built-in, so your phone would transmit a BT signal to the cassette adapter, which would then feed the audio signal right into the tape head just like playing a real cassette tape. More on reddit.com

What’s wrong with the aux? I would just use that. FM transmitters are so annoying and a true last resort. Even cassette/aux adapters are better. My previous 2006 Malibu didn’t have an aux OR cassette so I was stuck with a transmitter to play my music. Constantly fighting to find the right channel, constant static, etc. So grateful for Apple CarPlay in my new car

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Personally no, and I've given up on them. I switched to a tape deck with a 3.5mm audio jack for a while because it was overall better to me. If you dont have bluetooth or 3.5mm audio input in your car but do have a cassette tape deck, I'd recommend trying that. It still isnt great but I liked it better. E: there was one cassette bluetooth adapter I picked up to use in my old 98 monte carlo that I was pretty impressed with from amazon More on reddit.com

None of them. Fm transmitters are all pretty much shit. They used to work great years ago but fcc cracked down on the signal strength and theve been shit ever since. More on reddit.com