I usually run a skid plate, but the track I run on once has a long whoop section that I couldn't go straight through. Tried a lot of things and found out it was the skid plate. Not as bad with the DE plates, and definitely worse with the Associated plates.
If you have a bunch of forward momentum and you hit a big enough bump causing the rear to bottom and you have a piece of plastic protruding as opposed to just smooth aluminum, it wil cause the rear end to be jostled slightly causing you not to track completely straight.
Yes, the majority of the times I run DE skid plates, but if I find myself getting knock around on a bumpy track, it's the first thing I remove.
I'll be running this season at a buddy's track (he has a lot of land, and build a 300ft. track on it.). Perhaps I'll used the skid plate there as it's kinda back yard fun and practice, and remove it for competitive events at other tracks in NYS.
Although, they do have transponders and time laps as well as put out rewards and trophies at my buddy's, so maybe the skid plate will be off more than it is on if what you say is true with the handling.
I'll have to give it a few go's myself and get a feel...