Admittably a welded diff isnt the idea solution, it can be a bit unforgiving in the wet but for fast road use in the dry they are fine. The extra understeer isnt a massive issue, although I'm not a great driver so it's likely I'm not pushing the car hard enough.

An LSD from another Volvo won't fit without some major alterations which are likely to be costly and possibly might not work and a custom made one is probably out of financial reach for most of the people on this site.

Rally cars traditionally are fitted with plated diffs which under most circumstances are locked most of the time. Some of the RS500 touring cars ran in the BTCC back in the 80's were fitted with spool diffs.

Aye Monka, as VND says mine is dropped 2" and welded and is my daily. The negative points have been covered. Harder to park/3 point turns and faster tyre wear. IMO It's not that much worse though. Also those who say it will constantly want to go sideways and will try and kill you etc are talking out of their ar$e. Just take it easy in bad conditions (when you don't want to play) and you will be fine dude.