PD set up a ring around your planets, if you look at Vellos or Toms area you will see them, they are the large dotted rings. Any enemy fleet that moves within that ring and is spot able from sensors (fleet or planet based) will be targeted and shot at every turn. Use to be a 20% chance for the destruction of each ship, but Dave changed things recently so they are stronger closer to the planet they originate on. Just to give you an idea, I had on fleet of 300 cruisers show up in my space, within the targeting space of 3 PD. I killed 150 of them in one turn. Best thing is the damage to their fleet occurs with no possible retaliation.
High taxes lower your production rate of goods. Most people don't find this significant and run 20% tax, I don't particularly care and run the default 7% so I don't need to waste time changing it. The other factor is that upkeep of facilities is based on GDP, so increasing that tax rate increases the upkeep you owe, but you usually end up with a positive balance from any increase.
"Goods", as in, "everything other than cash"? By how much?
Also, there are two tax rates.
