Re: External lighting.
i have the led tail lamp/brake lamp bulbs and they will set off/trip your dash light. i did not add resistors but a small piece of black electrical tape to the dash light panel. you would have to add resistors in order to eliminate the dash light from tripping.
i also have hid's for my lower beam headlamps... no issues with the mccullough kit. however some cheaper kits will create issues.