I have a 03 Grand Caravan Sport 3.8 FWD with 3kw stereo. The electrical system shows no signs of stress, but the gains are all below 50% because I still have stock interior speakers. My question is what order should I replace the following?

1. "Big 3" - Grounds for battery and engine, alt to bat+
2. Battery - Thinking of going with Optima Yellow Top
3. Alternator - Not sure what amperage the stock one is but I'm pretty sure it's HO stock. I'm not sure I need to upgrade it.

Any input is appreciated. Thanx.

 

That's the exact order! Try the Big 3, if that doesn't work get a good battery (deep cycle, yellow top, kinetik, etc) and finally if both of those don't do the work which shouldn't be the case get a 150-200 amp alternator.