lol, I'm one of the "plug-ins work fine" guys, at least for my hvac.
I switched out the green filter for a blue filter & used a set of the white 5smt plug-in led's. Also used a set of blue insert knobs.
Not as bright as Jp7's yellow/amber hvac, but they're a lot brighter than the incandescent bulbs that were in there.
My cluster has my modded plug-in bulbs. I left the blue filter color on the back of the overlays (I was lazy & didn't want to deal with calibrating the needles) and modded my own 3mm white led bulbs with 3mm green led's. The green still shows through the blue filter fairly well & it's much easier to see now than the old bulbs were.
I'm planning on switching my cluster back to blue as soon as I get my 5smt blue led plug-in bulbs.