KB or Vortech, either is good, depends what you like. The Vortech will be MUCH cheaper, have better top end and probably easier to install. The KB will make power instantly, not have quite as much top end and is more expensive but people love them because you can blow the tires off the car in almost any gear at a low RPM if you want. For brakes, just convert to the Cobra brakes unless you NEED to have some crazy road racing setup.
Basic generic PI build:
-Block gone through and .020 over
-Stage 2 ported heads
-Comp 270 cams
-All the "bolt ons"
If KB you don't have to worry about the intake, if Vortech honestly the stock PI intake is fine. For your automatic, if you have a 99-03 car your 4r70w is good for about 500/500 hp/torque. If you are lucky and have an 04 you've got a 4r75w which is good for more and has a better pump. Either way do the J-mod, look on the TCCOA forums or their video on Youtube on how to do the J-mod. Car will shift much faster and harder, you'll bark the tires going into 2nd and possibly 3rd if you are flooring it. Oh, and a better stall converter will do wonders. A big power car with an automatic and a good aftermarket stall is going to stay streetable longer than a stick will and is going to be faster in a straight line than the stick will too.
Edit: There is also the Tork Tech kit which adapts the 2V for the Cobra M112 Eaton blower or any blower that goes onto an 03/04 Cobra really so Whipple and KB head units for the snake will work too. The kit is $2k sans blower brand new and you can get a good take off Cobra M112 for $300 all day on CL or Mustang forums. With that said, a good used Vortech is in the $1500 range blower included and is easier to install.