Not that I can find any specs that are in the same language/units as any other tuner I can find, but:

FM:
Sensitivity typ 1.4uV (test conditions 30db S+N/N)
S+N/N typ 64dB
THD+N typ 0.07%
Adjacent channel selectivity 90dB (test conditions distance +-200kHz, audio -30dB, ref=audio at rd input=17dBuV)

AM:
Sensitivity typ 4.0uV (test conditions: 10dB S+N/N)
S+N/N: typ 50dB (f=1000Hz)
THD+N: typ 0.35%

If you're interested, the datasheet is available at http://www.microtune.com/products/1384_Series.html

Hugo