check the hoses for blockage?
when you pulled the first thermostat out was it in one piece of did it break? Did you make sure all of it was there and none went into the block?
also I know on E46 models there is a sensor for the fan in one of coolant lines. It triggers the Aux fan, without it the car might still overheat. (I had this issue).
outside of that make sure your radiator isnt leaking somewhere. just as a precaution.
We all get the urge...Saturday early morning...nothing to do till noon...
The aural sensations of 1st gear WOT
**CGM **(Certified Garage Mechanic)