but I need some information please guys and girls

What tool kit will I need to put in the back for a just encase moment! (what tools)
I also have a kph clock with a sticker on the plastic. I want a mph clock! Can I just take one from a l model, take it out of the housing and fit it where mine would be? And I am guessing i'd need this little thing to convert the kph to mph signal.?
What else do I needto know?

Thanks!