Quick info
The rear camber is corrected by shimming the upper control arms (links) outboard. Add washers between the body and upper mount. Each washer provides 1/2 degree of positive camber. Use thread-locking compound with each new fastener. Be sure to add the same number of washers to each bold.
parts
1 - Washers, use 3/8 galvanized washers (from Home Depot). For the Eibach Pro-Kit (1.3") drop, I used 2 washers on each bolt. And you got 4 bolts, hence you will need a total of 8 washers.
2 - you might need new bolts if you put more than 2 washers. If that is the case, use M10 x 45mm bolts. Home Depot has them, Four fine thread machine screws (M10 x 1.25 45mm bolts), (Home Depot part #18531). The are cheap, so pick your bolts of varied length (any from 30mm to 45 mm is fine), and if you don't need them, just return them.
3. Tools (14mm socket and ratchet)
Procedures
1. Jack up the corner of the car that you are working on. Use stands if you have them, I definitely recommend fixed stands to put under the car. Make it a must. Safety first!!
2. Take of the wheel.
3. See the 2 M10 bolts holding the Rear control arm, I will refer to them as bolt1 and bolt2, in no particular order.
4. Unscrew bolt1 out. You will need so force to loosen the screws. This is where handy tools come in if you have them.
5. LOOSE bolt2 only, just enough so you can slide the washers into the bolt1. Once the washers are in, screw bolt1 back in. In enough that it wouldn't come out. Don't tighten it all the way as you will need to put washers on bolt2 now.
6. Unscrew bolt2, and put the washers in.
7. Tighten both bolts, and you are Done.
8. Do the other wheel. and I hope you enjoy your cheap, but effective rear chamber fix.
i personally have the eibach sportlines, i have 3 washers in each bolt, total of 12. and that gives me a -0.7º camber in the rear. i would definitely suggest getting an alignment after a week.