I went for LED running, turn,reverse and brake lights on my 1976 Spider. I really like the resulting 'fresher' look...
I used an electronic flasher (my old can flasher was about dead anyhow...), which caused me to switch to an LED for the indicator arrow.
A few notes - LED-based 'bulbs' get hotter even though they do draw far less current (hence needing the electronic flasher). This is because an incandescent bulb RADIATES (wastes) infrared light, basically heat, but that heat winds up far from the bulb in the end. An LED doesn't radiate infrared, but the power supply stage (which might just be a resistor!) generates some heat which doesn't go anywhere. It just heats the bulb base.
Some of the tiny dash lights are polarity-sensitive - if you try those, test as you go (they won't die if backwards - just not light).
Superbrightleds.com has good prices & descriptions.
A primary reason I went to LEDs was to avoid the need to take apart my running light assemblies to 'change a bulb' - the LEDs should last many times the lifespan of an incandescent bulb. That's why I did the dashboard lights and glovebox, mirror and trunk lights in LEDs as well (not quite as satisfied with that change - dimming works poorly, and some bulbs have poor radiation angles...).
My hope is to never again need to change a bulb!
LED headlights are not quite ready for prime-time, in my opinion. But I'll keep checking on their progress...
50 years from now - how are we going to restore a "classic" microprocessor based modern car?? Alfas - 1980 Spider, 1987 Milano, 1976 Spider