Ohhh lord. I couldn't tell you anything more than a cursory google could about update path. What I do know about the anti-skating weight is that it's got three little notches, and I find it functions best in the second notch
Hope that wasn't too technical for you!!
I will say this. In my apartment. Under my particular test conditions. (Beware the wrath of the Rega Research fans) I found the P2:
1. Noticeably more sensitive to environmental vibrations. (I tried tripoding it on three brass cones, didn't have any effect.)
2. When I ran the calibration LP (there's a long bit that has no sound, so you can turn the volume way up *risky* and listen for motor noise.) a little bit of... I don't know what it was, it may have been the needle. But it was a faint something in the distance.
Disclaimer: I was thumping a phonebook on the carpet, switching the tele on and off, running the microwave, etc. in my search for sensitivity. The microwave really pissed off the rega.