You should not need the cluster.

You will get a tamper dot which will suggest the odometer might not be accurate but should not cause any problems with DMV just picky buyers.

I've followed a few EWS swaps as you are suggesting but never heard of a problem with emissions after but i don't know if it was required for those people.

Hopefully somebody will chime in that's done it.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)