The rear is way too soft right now, I know because I'm dealing with the same problem on my street bug
It's got the same behaviour and it drives me crazy. I think Clive is on the right track with the addition of 150#/in rear coil overs on top of what you already have. If you want to stick with torsion bars I'd suggest a stiffer 25mm bar instead of the 23.5mm which I think might be too soft still for the weight of the subie.
Normally, with a well setup beetle, turn in should be instant and direct without hesitation. As the suspension loads up it'll feel like it's turning sharper on it's own (a feature of the suspension design) and should be neutral with a tendency to understeer when pushed to it's limits.
Right now when your bug enters into a corner the weight transfers to the outside rear because its the softest corner. With the weight away from the front wheels they can't do their job so it pushes. To make matters worse, when you finally pour on the power coming out of the corner what little weight you had on the outside front corner now transfers to the rear as the rear end squats. Basically, the beetle is a point and squirt car at this stage, since there's too much weight transfer to do more than one thing at a time.