[Alpine TSi]

I have the stock 75 amp alternator in my 1G and run a 800 watt RMS sub amp and a 200 watt RMS amp for my speakers and haven't had any problems. I also have a deep cycle battery though. But just don't pound on your system while it is idling, that is a huge draw on your alternator.

An easy way to determine if your alternator is safe is to add up your total amperage draw, if it exceeds 120% of your alternators output rating, you need a bigger alternator.