I've actually done a good chunk of what you are looking for here:
GPS Coordinates & Velocity:
For this you can use the following Adafruit hardware:
- GPS Breakout
- GPS Adapter
- GPS Antenna
This sensor will give you the coordinates and the velocity when you use the Adafruit library. I would connect it using the i2c port and start with the example code "GPS_I2C_Parsing". You'll be able to remove most of the data as it is not needed in your example. You'll also likely want to convert the speed to mph (it comes in as knots).
I have not actually tried to stream audio from an arduino to a phone or anything but you can still get a noise level. If you just want to get a dB reading and send that you can do that one of two ways; analog or digital. For analog you can get something like this from adafrutit. This has a built in microphone (probably not ideal) but it also has the amplification circuit you'll need. You can always desolder the built in and connect your own. For the digital route you could go with something like this. Adafruit has a few different variants of this, it would depend on what exactly you are looking for.
I think you're best option will be a GSM shield. Wi-fi, in my opinion, would be difficult unless you are using your phone as a hot-spot in the car. (Probably defeats the purpose of doing this then). You can use the referenced shield to send texts, with data such as the coordinates, speed and noise level, and even make calls, for an audio stream.