I sprayed a little WD-40 down in there for each plug. Waited an hour and then slowly broke the torque on each one. I used a spark plug removal tool I got on eBay for $100. Made things a lot easier. The number for it on there is 291162131029. Good luck
Just take your time and go slow if you get a tight one soak it with your choice of penetrating oil and do yourself a face and but the 1 piece plugs they are alot more money but they won't break apart like the one that are in your car now.
84000 miles on mine. Did them this weekend and they all came out fine. I had bought the Lisle tool to remove the broke plugs and didn't even need it! Popped them loose about a 1/4 turn and soaked them in PB Blaster for an hour. Make sure the engine is cold.