Have you seen what GM stock is selling for ? Something under $10.00 a share.
My guess is that whats left of GM will be sold off within 5 years. Either that, or they are going bankrupt. Other than the 'Vette, their FULL SIZE truck and SUVs it seems that GM is loosing money on every US model they build. Unfortunately now that the price of gas has gone up so much the market for these vehicles is greatly reduced so GM is on a crash course to produce a cost competitive fuel efficient vehicle.
Saturn was formed roughly twenty years ago with the intent of developing the engineering necessary to remain competitive in the Automobile business. The original SL1 and SL2 were not bad cars.. when they were first introduced back in 1993. Unfortunately, after Roger Smith stepped down as chairman of GM, Saturn's budget was slashed and they resorted to reselling European Opel products in the US.
In general large car companies emphasis is on minimizing development and production costs, sharing parts across model lines (in an effort to reduce production costs) and on maximizing per unit profitability.
Given the greater reliability of modern technology cars, accessibility of mechanical components is now longer a priority. This is true of all manufacturers including Subaru.