I will admit that replacing the festoon bulb in the interior dome light on my 140 is the one change to a LED that I can enthuse about. I got a 480 lumen 43 mm festoon bulb purchased via Amazon back in 2017 and it definitely makes it much easier to find my keys if I drop them down by the seat at night. The stock dome light was useless.
https://www.swedespeed.com/threads/w...0/post-6195769
I also have Hella H4 headlights with the optional city light and I have installed a couple of LEDs in the city light position. I run these continuously as day time running lights. The actual headlight bulb is still a conventional H4 halogen.
https://www.swedespeed.com/threads/w...0/post-7126121