5 speed overdrive gearbox for M10 engine (best if it fits BMW 2002)

I’m after a 5 speed gearbox for a BMW 2002. I’m not talking about the dogleg close ratio expensive one, I’m looking for a 5 speed overdrive box so I can cruise in highway speeds with a bit less revs on the engine.
If anyone has one please let me know.
I know that E30, E28 and other M10 gearboxes would fit but I understand the speedo cable is different and the clutch activation is hydraulic so it would be a bit more complex to fit but depending on the offer It could be done.

Thank you.
Pedro