AtomHeart, I was telling my wife about what your car was doing while we were on our way to dinner tonight, and suddenly it hit me. It's already been mentioned before, but I too believe it's your traction control kicking in and shutting you down because the tires are breaking loose on your 1,2 shift, and the slightest loss of traction can make it kick in even when it's turned off. It drives me nuts on my car when this occures and if somebody does come up with a way to turn it off without having to pull several fuses every time, that would be great.
Posi traction probably wouldn't help that much, because a car with Posi is actually more prone to "fish-tailing" than a car with an open rear end. Stickier tires might help, but with the power the SRT puts out, you would probably still find some pavement somewhere that would allow it to break loose.
I really believe, the easiest way around the problem is to find the solution (once and for all) to turn the darned traction control completely off, when ever you want to.
If all you need to do is pull a few fuses, then it may be as simple as installing a few interrupter switches in place of the key fuses, much like I did with the fuse that controls the motor that lifts my spoiler. Then when you get bored with "acting up", you can flip a switch to turn the traction control back on.