What’s the best Forex trading system?

The one which increases your trading balance.

If you look for someone else to give you a fail-proof recipe, be prepared to lose.

Is $3k enough to get started in Forex trading?

It depends on your needs and aims.

If you need to live off your trading it isn’t enough, but if you look for a way to learn a new trade, patiently build your reserves, and have another existing income, it is enough.