Yes but small things soon add up to make a bigger improvement and you can tick them off the list too.
Yes, I did them both earlier this week. Made a massive difference to the gear change and the drive seems smoother. Made a really good car, better!Also just a thought, have you considered getting your diff oil changed as well as the gearbox oil ?
Myself and @Oldguysrule chased this very same problem for months on his 2.8. We replaced every bush on the chassis, prop bearing gearbox and diff fluids. The clonk was still present. That then confirmed to us the Pinion gear in the diff had lost its backlash causing the clonk. This then leaves slack in the drive train when your changing gears. You can adjust your driving style slightly and eliminate it being gentler with the clutch. So when I bought my M it had the same problem, I dropped the diff out and had it all re-torqued which cured the fault straight away.
Lee