Lower control arms

[tc3drivers]

My car has 192,000km on it and I'd like to change the lower control arms and ball joints since the rubber is worn out in the arms. I went to the dealer and the prices are outrageous. I called the local recyclers and they list that only the Vibe lower control arms fit the Vibe and Corolla/Matrix arms are not compatible and of course they are all out of the Vibe arms. Looked on ebay and the sellers list that the generic arms and balljoints fit Vibe/Corolla/Matrix. Anyone here have experience with changing the arms or using Matrix arms on a Vibe? Is there really a difference or is GM trying to get me to buy GM parts even though they are the same???