Are you talking about replacing incandescent bulbs with LED replacements? If so I can tell you how it went with my 18.
I replaced both the front and rear directional bulbs and back ups with LEDs without problems. I replaced both rears first and did not get the fast indication but when I added the fronts I did get the "hyperflash" indication. The actual flash pattern is normal only the clicker you hear clicks faster. The flasher is electronic and is telling you that a bulb is out. I did not add load resistors to fool the flasher. No codes or errors indicated on the dash but there may be something in the OBD saying lamps out. All the lights are noticeably brighter and I like it.
If this isn't what you asked .........Never Mind.