1. most likey it does not have RCAs out.
2.It's called a Line output Converter (LOC)
3. The cheap ones will sound cheap, a quality one will sound good.
david navone makes good LOCs
www.davidnavone.com
You could use:
N-7V if your amp has a crossover on it (nearly all do) and you may add a door speaker amp later
N-85V if you will only ever add subs (no door speaker amp)
my vote would be the full range N-7V