Sigh. I just type a reply to this, but I was too thoughtful and by the time I had finished it had auto-logged me out and I lost it all....
This is my 2009 A50, which is a work in progress ( please ignore the sun damage, long story short I keep it inside most of the time now ).
I use a Pyle PLMCA10 100w Motorcycle/ATV/Snowmobile amplifier. I replaced the crappy speakers with Scosche 4" 3-way 30w/150w peak for much better sound. I use it with a Samsung Galaxy Player 3.6 Android device, which has an FM radio and even a GPS for turn by turn navigation when it is in the mood. The mount is also Scosche, and to its right are the controls for the amp which I cobbled into the plastic ( the switch to the left is for headlights - off/running lights/headlights ). It connects directly to the battery, but I installed a key switch to turn it off ( and turn the alarm on ). Those are Kymco aftermarket mirrors the windshield is mounted too, and it keeps the gravel/bugs out of my face and help alot with the rain...