led tail and brake lites are a cinch,some led turn signals
need more (load) than just resistors > electronic flasher.. which you may not need if you leave the front signals stock..
none ,one or two t.s. indicators affect the circuit(if you modify the instrument cluster).. ive found some good info via google..watch your polarity
some leds are sensitive and wont work reversed. i dbl check with small 12 battery charger b4 installing... protect those ulta thin led wires.. vacume tubing and or fuel line make good conduits and splice points, paint on electcical tape over a tight telegraph splice will fit inside.
have fun on your bob job

Switching to L.e.d. turn signals will make your signals blink fast.  The stock flasher is made to blink fast if a light-bulb burns out.  You can buy load resisters for l.e.d. lights but that kinda' defeats one of their best features.  Lower power consumption.  Replace the stock flasher with an automotive "thermal" unit, and it will flash at normal rate no matter what the load is.  $6 to $10 US at checkers,autozone etc.