I've had both the problems you're dealing with. The cluster comes out a couple of inches very easily after the under dash panel is removed. But to see what you're doing the speedo and maybe the oil line, that's right oil line, need to be taken off. If you need to disconnect the oil line (yes it has oil in it) do it at the other end where an oil drop won't be noticed. When you replace your bulbs there are three types, one large and two small. Two of them appear to be interchangeable but aren't. One small bulb type comes with its own socket the other doesn't.
My engine shake was solved by new motor mounts.
1983 300D Turbo
1995 E320 Wagon
2001 MR2 Spyder
2001 Subura WRX Sedan