ok.
I drove a two way at a road course event in Gainseville and I slid it through one section a few times. It felt absolutley amazing, I could go to lock, then transition and it felt like it didnt even want to spin out. To ME, it felt like I could drive more agressivly with a two way and not worry about spinning out as much.
The whole thing about welded diffs breaking. I drove mine for over a year. Daily driving everyday 50-60 miles. All around town and tight corners. I also slid 3+ nights out of the week. I never had one problem with mine.
My friend Tom has had his welded for over a year with no problems. He daily drives 60+ miles a day, and he ran it for damn near 2 months with all the fluid drained out of it. If the bearings have even the tiniest bit of fluid, you're golden. He was also sliding 3+ nights a week with me.
If the person that welds your diff really knows what they're doing, that diff will hold up probally longer than a two way.
I still really want to get a two way just cause they feel absolutley amazing to slide on. Until I really do feel like paying all that money for a diff, when I could just weld mine for like $20, I'll stay welded.