Get the alternator from Autozone I think it is that has the lifetime warranty - kill it, take it back.
I'm running stock alternator -> relay -> two yellow tops -> amps (roughly 2,000W RMS), all with 4 gauge (currently... upgrading soon to 0/1 along with big 3). I've had my car for around two years now and only had to replace the alternator once... about a week ago.
The HO alternator is your cheapest and best solution, alongside upgrading the wiring.
~vR