Very Bad Vibration

[s1ngletracker]

I think your excessive toe + bad wheel bearing could definitely be causing it. You're putting a side load on the wheel bearing (which has play in it) and you could be seeing an oscillation in the dynamic toe of the wheel. I'd fix those problems before you worry too much about throwing more $$$ and parts at it.

I've used the precision joints and never had problems, nor have they caused my driveshaft to be crazy out of balance.

Notchy U-joints are totally normal (seen it on almost every DSM driveshaft) and shouldn't be causing that much vibration. It'd have to be really damaged and in need of replacement. Can't hurt to change them though, they're pretty cheap.

What it sounds like to me is that you may have borked driveshaft angles. I've never done an AWD swap so i'm not sure how easy it is to mess up, but if you have too severe an angle on one of your U-joints, you can and will get good amounts of vibration. Could also be caused by a really bad carrier. Although at 5mph I wouldn't think the shaft is spinning fast enough to even cause that much vibration.

Are you sure you don't have something rubbing on the bent knuckle, driveshaft rubbing exhaust, etc?