Originally Posted by Martin Hofer

a narrower rearend generates more steering

that's the reason why modern cars like tamiya or bd5 are wider up front than in the rear

note that it'S a difference if you narrowen it inboard or on the hexes

sdw was a different car at a different time
the short arms where used up front by that time to compensate the lack of steering angle
but today we can cure that and thus don't need that