I prefer Alpine over just about anyone else for head units. Their monitors and changers are also top qulaity, but very expensive as well.

As for an amp, clean power is the key. PPI, Phoenix Gold, JL, Arc, are just a couple name brands that are proven.... For the sub, a nice class d amp from Memphis, DEI, MMats, Arc, etc..l would work as well. Just make sure your subs's final impedance matches the amps max power output...