I think that deler gave you bad info...but it also depends on the soil conditions in your area.
For strictly loading work, no tooth bar is necessary (assuming the pile of material is loose and not packed solid).
However, anything solidly packed, those teeth would put more pressure (for the area) then the cutting edge of the bucket (High school physics there...) That would result in greater digging force.
Anyway, the tooth bar is a value-added addition to your tractor. I paid $305 for a 54" tooth bar delivered from NC to southern PA. $400 might be right for your bucket width, but it sounds a bit high...I'd at least try carverequipment.com and getting the delivered price of a tooth bar that is the correct length for your tractor's loader. Delievery costs might be the killer for buying from Carver...then again, maybe not.
As far as installation, that's pretty easy. Just mount the tooth bar on your bucket cutting edge (there is a slot on the bar to go over the cutting edge), drill two holes (probably ¾" diameter) and bolt it in place. Although the bolts are supplied, I'd recommend using stainless steel ones to minimize rust (so you can get that tooth bar off sometime).
Bottomline...buy one...
However, for your task of removing those juniper bushes, a tooth bar may not be the best implement. I don't know much about juniper (other then it's good ground cover) and what their roots would be like. Siince you've dug several up already, you should know if you could just dig around and yank 'em out, or if you had to cut through a lot of roots. I don't have a box blade, but I'm wondering if cutting them down with a rotary cutter, then box blading to drag out the roots might be a better method. You may be able to rent the rotary cutter and box blade from a local rental store.
I'm sure other members will make better recommendations as to how to remove those junipers. I'm also sure most will agree to buying that tooth bar.
