I can buy just the thermostat at local part stores. But I've read that the entire thermostat and housing need to replaced together. Has any replaced just the thermostat? It's an R56, '07 S
The housing and/or gasket is prone to leak, especially in '05 & '06 MCS cars. Hence the recommendation to replace both.
Generally the housing is fine, I replaced my thermostat and housing today, I could have saved about $30 because I did not need to replace housing it is fine. If you need a used perfectly fine therm. housing PM me Ill sell it cheap.
I have been told that the housing can warp. Not sure if this problem is unique to the first or second generation. You will just want to make sure that you inspect the old housing before reinstalling. Nothing like having to redo a job almost well done.