For turn signals you do need a new flasher otherwise it will just make this horrid grinding noise and not work, from superbrightleds where I got mine the part number is
CF13JL-02 (for a B14 anyway), and for tail/brake lights (center brake light it doesn't seem to care) I think you need load resistors but I am running without them just fine, all that happens is if you have the cruise switch on (the one by the dimmer) and you push in the clutch while not braking the cruise light on the dash flashes... it's weird I know, but it only happened since I did the LED conversion. Everything else is pretty much straightforward pull out the bulb and put in the LED bulb