I would go in this order...it is what I did, and was more cost efficient and noticeable.
Gears
Exhaust
Ignition
Pullies
REBUILD IF OVER 80K
Intake
Cam
Heads
Rockers
and then a Blower if you aren't satisfied, I thought I was but you know how that goes
Nitrous is fun, but a cheap way to win, and it tears on the motor.
Dustin