Thanks to all the members that contributed to this thread.
I found this thread after trying to diagnose the same problem for the past week and half.

I recently had four new Yokohama tires installed and an alignment done, after which my car started pulling to the left under acceleration and back to the right when not. After lengthy troubleshooting by my local shop, the problem persisted.

At a meeting this past weekend, my local porsche club members suggested I check rennlist.
After finding and reading through this thread, I swapped the rear tires from left to right and the pull I had been dealing with reversed itself.

At last, a solution!!!! I have all four Yoko's going back and I have four new RE-11's on the way.

Thanks again.