mm, the most i've done is 300kts to 10nm at 1500ft on the 732, usually dropping the landing gear at 270kts with speedbrakes and at 210kts selecting flap 40 and lowering the speedbrakes in level flight results in a rapid deceleration and flaps going down on schedule, not very comfortable with passengers and you do have a bird strike issue too by flying low and fast, but on a 35min flight, going high speed below FL100 can mean a 5 min difference or more if you flew at a high speed cruise too...
