Yes old post, but very interesting to me and i do have an opinion...
Your short wheel base absolutely runs as straight as a long wheelbase. Thats until it doesnt.
All things equal, the longer car has an advantage in staying straight and in recovering when that is even possible.
All spinouts are different but consider this with me for a math moment.
If a short car and a long car both kick out 2 feet at the back, that maybe 5 degrees on the short car but only 3 degrees on the longer car.
Longer car would be easier to control and recover from this perspective.
Equally its moment of inertia in the yaw rate would be less.
Thats from the perspective of how much the rear end snapped out.
Now if both cars rotated 45 degrees (a ridiculous amount), i cant really say either would be recoverable... maybe, maybe not. Though i am positive i'd rather that extra 2 feet of crumple to bleed off energy.