SpeedKart tracks are automatically loaded without you having to modify anything.
function SK_BuildTrackList()
{
//
%pattern = "Add-Ons/SpeedKart_*/save.bls";
$SK::numTracks = 0;
%file = findFirstFile(%pattern);
while(%file !$= "")
{
$SK::Track[$SK::numTracks] = %file;
$SK::numTracks++;
%file = findNextFile(%pattern);
}
}
This code literally finds all of the files that fit the pattern ( * is called a wildcard character and any text at all can go there ) and loads all of those tracks. You do not need to change anything.
As far as Vehicle_SpeedKart goes, I'm pretty sure you're actually not supposed to replace that. In the code, this is the code to load the kart vehicles:
//load the actual karts
// these are a feature locked version of the karts from a while ago
exec("./karts/speedKart.cs");
The two comments serve as a warning that newer (updated) karts may not work. However, if you still want to try, you can delete all 3 of those lines inside the server.cs file. Then all you should have to do is add a line into gamemode.txt that says:
ADDON Vehicle_SpeedKarts