They told me that, if you used the leaded fuel, the tailpipe will be totally closed and will harmly effect the enigne. So they want to remove the tailpipe and put another.
I think they mentioned something about filter, and they will calibrate how much Octane is going out the tailpipe. And there are two plugs that should be replaced I saw a number on them like 35 or something, and the plugs that are on my car and should be replaced, they have green writting on them with different numbers.
They said, they would like to replace those green ones with another ones, just to make engine know the leaded fuel or something like that.