Might be total bollocks but I heard that a Blackbird speedo fits in the cluster and the electronic drive can be fitted to the gearbox. Then an electronic module can be fitted between the two to calibrate the speedo. Sounds like a lot of $$$ and a lot of bother but at least it would look nice and neat. Any truth to this method or is it just bar room bs ?

 

Never heard of it, but I'm sure there are several ways to do it.
I'd rather just remember that I'm about 5% high on the speedo, though. I only use it for a rough estimate anyway.