I ordered some warm white LED festoons from Aliexpress and they weren’t as bright as I was hoping for. First I tried the 6x 5050s and then the brighter 6x 3030s, which ran hot. I also didn’t like the tint.
However, I’ve been quite satisfied with the 48x 3528s using a festoon adapter similar to the one posted by Scallywag. Also the tint is decent. This is the one I got:
https://www.aliexpress.com/item/32263082885.html
It barely gets warm and it’s significantly brighter than all the other festoons I tried. Of course you’ll need enough space in your light compartment.