Your friend is full of crock!

A fully modded Focus with a super high center of gravity versus a fully modded S2000 or ITR? Right. What planet is he living on?

If all cars had the same bolt ons the ITR (with a LSD) or the S2000 which is RWD would run circles around the Focus.

Even at an autocross you can tell which cars are faster than others by what stock class they are in. S2000 = AS, ITR = DS, Focus SVT = GS, Focus = HS. AS being the next fastest group and HS being the slowest group.