Its a doable DIY project but a major one. The biggest issue will be the the bolts for the outer bracket that you are replacing will be rusted in. If they don't come out easily, do not be tempted to apply more and more force because they will snap off. You'll probably need an acetylene torch to remove them.

Heres my story.  When I got my mini 2 years ago it was not long before i noticed uneven wear of my tires all 4 on the outside edges.  robably toed in I thought.  So the shop gets the front end in line but says there is no adjustment in rear.  The rear continue to wear poorly and the front look pretty good.   So to amend this I am considering the adjustable camber/toe bracket for the rear end.  So if this is a good fix is this a project for a novice without a lift or special equipment.  I have a new set of tires that I plan to install after this once we have 4 wheel alignment.

Thanks, Jack