The resistors should already be in the bulbs so you don't have to worry about that. You will need to run the electronic flashers though. The old style flashers won't work since the LED bulbs use a lot less power.
Superbrightleds.com has a resistor you put between the pos and neg leads to each of your blinker light circuits. They're around 8 bucks a piece. This solves the problem of extremely fast flashing.
I've just installed LED's everywhere but the front blinkers. That way there's no issue.
By the way, LEDTronics.com is the place to go for 1156 taillight/brakelight and reverse light bulbs. I got my interior stuff from Superbrightleds.com Both have superior customer service.
Lindy