There are a few reasons your V70 would wheel spin less than the 850R (being auto is certainly a factor too).
* Softer spring rate of the V70 vs the 850R (Higher ride height would - if spring rates were the same - equate to more wheel spin)
* Taller and more compliant (effectively equating to less spring rate) tyre sidewall.
* The V70 may have a smaller dia swaybar
These are also reasons why a big swaybar in the front of an FWD P80 is not good for handling/performance. :)
The clutch packs in the stock LSD are quite tame and with higher kms are likely to be fairly worn out by now.
The Gripper is a good alternative to the Quaife LSD. I recently drove a '98 S40T4 manual with one, a little harsh but REALLY good.
Here's a link -
If there was enough genuine interest locally to justify it, we'd look into offering these.