Honda accord v6 exhaust cold air intake

I'm driving a honda accord 3.0 v6 vtec auto 2006 2 door. It has duel exhaust stock
1. How much faster/louder would my car be with just a cold air intake
2. How much faster/louder would it be with new exhaust system (mufflers and pipes)
2. How much faster/louder would it be with cold air intake and new mufflers
4. How much faster/louder with cold air intake and whole exhaust system

1. There will be no noticeable difference in speed or power with a cold air intake. Where this would make any real difference is on the track, not the street.
2. Depending on the exhaust set up, the car may get louder but it may also get slower. Engines need a certain amount of back pressure to function properly and make power. Too often people go for loud exhausts, just opening it up, removal of cats etc and it robs the engine of power. Fools think they are going faster though because it's louder. If you must, just change the mufflers. Leave the rest of the pipes be.
3. Again, no noticeable difference between using the two and it really depends on what combination you use. Sometimes you put pieces together than should equal more power and you go the opposite way.
4. See answers 3 through 4. I will add that with headers and the right freer flowing exhaust, the engine will breath more easily, temperatures will tend to stay down and in the right ambient outside temperatures, the car may pick up a few hp.

It's really tough to add hp to an normally aspirated engine, meaning one without a turbo or supercharger. Having said that, don't think about trying to slap one on there. If you want a turbo or supercharger, sell this car, get one that has one and start the tuning process.

To really tune a car for more power you have to have a baselines of what it is putting down stock. So you need to have the car put on a Dyno. Once you have the stock output, you can start making modifications, and then you must go back to the dyno and see if you've gained hp and/or torque or lost it.

Tuning for more power is a process. Too many people just try to slap on parts based on the manufacturers claims of 5 hp here or 10hp there. Real tuning doesn't work like that. Go find the Honda enthusiasts web forums and start reading.

Unless your air filter is clogged there's no benefit from installing a cold air intake. Changing your exhaust could cause your car to be slower. The engineers at Honda know what they are doing.

Short answer: Not faster, just louder.

Gray area has 2 wrong. Right idea, wrong theory. Engines don't need or want backpressure. They need "just enough" exhaust flow to maintain velocity, which promotes scavenging. Too large exhaust (anything over factory in your case) creates a loss of scavenging, which hurts power. Nothing to do with backpressure.

Realistically, the further back from the engine you get, the less effect modifications have… Converter, mufflers, neither on a modern car are really restrictive (unless damaged) and unless/until you modify the actual displacement/fuel demands of the engine, exhaust mods back that far won't help. Properly sized headers may help, just depends on how good the factory manifolds were. Normally they are somewhat restrictive due to space, reliability, and sound restraints OEM.