My rule involves refusing to discuss any other car than the one you called about. This means that if that car is no longer there, the phone call is ended.
Other than color and trim, all those details you list DO matter, and you should have decided firmly on them before choosing specific cars and calling the dealers who are offering them. If I've decided that I'm going to pay $3500 for an 8 year old GM compact station wagon with a/c and automatic transmission and under 70,000 miles, that the dealer has listed for $7950 (as was the case with my most recent purchase), I am not going to discuss any car that doesn't meet all those criteria. I am not interested in paying $3500 for a 10 year old car with 100,000 miles, no a/c, and a manual transmission, which is the sort of thing the salesman would be trying to push once I'd made it clear that $3500 was the absolute limit.