Very Difficult, but Look Great When Done
You definitely should have some wiring experience and be knowledgeable about making things work with what you have to install these gauges. I had to dremel out quite a bit of my stock gauge housing and figure out a way to keep the little circuit boards on each side connected. The temperature sender was a different size than stated, it was 1/4 npt so I had to order an adapter, same with the oil pressure sender. The transmission sensor wouldn't fit without heating the bracket with a torch and bending it, and the o ring came broke, so I reused the old one. Instructions are pretty vague also. Took me 5 or 6 hours of tracing wires and getting the sensors to fit, but they do look great when finished. I understand these fit a wide range of years so everything won't be plug and play, "direct fit" seems a little off though.
Intellitronix® - Direct Fit LED Digital Gauge Panels