Are E21 instrument clusters interchangeable?

[petroscf]

I was thinking of repairing and maybe modernizing an instrument cluster
I saw these guys : http://www.bavrest.com/
They show only work for E30s but they also do E21
However, I would rather keep my cluster as is, and find another one in order to send them for rebuilding
This is why I am asking, if there 's interchangeability between clusters

[E21-driver]

Hi.
You mean inter change between e21 and other e21 clusters? They can be changed. But as the e21 speedos are mechanical, each has different ratios. As far as I remember, there are also differences between the fuel gauges and the rev gauges between four and six cylinder. You should use all gauges from the same engine, otherwise they will not show the exact values. Or stay close to your engine and speed ratio as close as possible.
M.