I have a '09 GT/CS with M90 Roushcharger.
I occasionally get what feels like missfiring on a cylinder.
I don't know if it's plugs, injector, coil, etc.
The car has ~22k miles, and the problem only happens on rare occassions.
I never sets a code or service engine soon light.
So, I want to start with replacing the stock spark plugs.

1) Is there a special techique to removing the '09 spark plugs? (mine does have the brown plug boots). I can find info for the pre-08 spark plug removal, but not much for the '08-10 plugs.

2) What replacement plugs should I use? I have installed VMP's upgrade kit to this Roushcharger (smaller pulley ~8.5psi, Steeda cold air box/filter, SCT tuner with VMP's tune).

 

No special procedures to replace the plugs, make sure the gap is good (.030-.032) and just put a little anti-seize on the threads. Helps if you have a little piece of vaccuum hose and slip it over the end of the plug so you can start hand-threading the plug into the head. I use Brisk X0R14YS plugs in my '09 with the E-Force.

 

Mid 08+ have a revised head and plug setup so you don't have to worry about the plugs being fused (thus breaking) in the head.

I can't provide any advise on the plugs specifically but for FI you typically want to run a heat range colder than stock and gap the plug smaller than stock for FI application as jpplaw mentioned.