EDIT These do not work as expected on my Jeep although they seemed to work fine on Mercedes. So you may need to order different bulbs.
There is no need to get separate LEDs and resistors. Just get CAN BUS LEDs like this:
I just installed these and they look great. There's no hyper blinking and they are much more visible than the stock bulb.
The stock bulbs are 7W. If you use a 6 ohm resistor with a standard LED bulb then you will draw 24W just through the resistor! That is way too much and the resistor will just get hot and potentially cause problems with wiring that is designed for a 7W draw (although admittedly it's probably OK).
Just get the CAN Bus LEDs and they will draw just enough extra power to not trip the sensors and you won't have to wire a resistor. This took me about 10 minutes to install. The hardest part was just removing the taillight assembly.
EDIT After having the engine on for more than a few minutes, it seems the error message DID pop up. So even though these are advertised as CAN Bus lights, they seem to have issues on the Jeep. I emailed superbrightleds support as these have worked in other cars without issue. It may be an issue specifically with this light and Jeep.