alpine type x subwoofer?
i would buy a mtx class d technolagy at least 600 watts and run your speakers as mono, that will give you max watts and a study rms
What Amplifier to get with JL Audio 10 inch W6 speaker?
JL audio 500/1 would be the best match, you could also go with alpine MRP-M650 , this one will be cheaper, and it gives 400 watts output at 4-ohm, so ur best bet would be alpine.
Whats a Good song to play on my friends alpine 15 inch subwoofer?
Reason to Believe by GTR (GTR is Gareth Emery) Super Sonic by Leo G Immortal by Ceylon but be aware, this can become dangerous for the glass of the windows :-)