Johnson GT and Evinrude XP

[Evinrules NL]

I own a Johnson 10GT(2001) and I'm planning to buy a 20hp Evinrude XP. But what is the meaning of "GT"and "XP"?<br /><br />Cause on the inside of my Johnson it says that it's a 10hp but on the serialplate it says 11,2KW(15hp)?<br /><br />So I want to know is it a 10hp or a 15hp?And is that Evinrude 20hp XP a 20hp or more?<br /><br />And are the parts the same as for a normal engine?<br /><br />Greetings from the Netherlands