Do a search on HICAS, I cant recall.
Only thing with the speedo facia is that it will only go upto 110mph, then you will be off the clocks and spinning round.
I've never known it to do any harm though. If you have a GPS device that can let you know your speed @ 110mph + (if you go there)
Speedo also means you dont have to mess around with telling people "it did x amount of kilometres, before it was converted to miles and has done x amount in miles since"
The speed limiter will still be in place with just the facia changed, but you can always cut wire 53 on the ecu which will delimit. Unless your ecu has an aftermarket chip, in which case it will already be delimited.