I would probably start with a BB60C for EMC it already has >50 dB spurious rejection, which is plenty for precompliance testing of unintentional radiators. For intentional radiators, I might just buy a simple high pass filter for looking at harmonics, and a low pass filter for looking at frequencies below the transmit frequency.
Preselection is a pain, and expensive, but when you need it there really is no good substitute. External high pass and low pass filters e.g. from Mini-Circuits, will work for many applications, but they do require manual setup.
