This is what I used;
www.banggood.com/TDA7492P-50W50W-Wireless-Bluetooth-4_0-Audio-Receiver-Digital-Amplifier-Board-p-1003047.html?rmmds=myorder&cur_warehouse=CN
TDA7492P 25W+25W Wireless Bluetooth 4.0 Audio Receiver Digital Amplifier Board
Product ID: 1003047
Price:
US$
11.48 also look here for other choices
www.banggood.com/search/bluetooth-amplifier-board.html
I put one of these in and hooked speakers to it a listen to music from my phone, works good, but would do better if I got some better speakers. I added a multiconductor cable and put remote switched on the dash for power, volume up and down and move forward to next song. If you know what you're doing, it's easy and can use any speaker you want.