I agree that the Grob is the least "304-like" of the aircraft I
mentioned, but it will accelerate quickly enough to make the important
points about spiral dives, redlline speed and recovery, even with the
spoilers out, and will float well enough to emphasize the issues of
speed control on landing. I agree that a Duo, K-21 or DG-1000 would be
better for the purpose, but these are less available in the local
rental/instructional fleets.

Ray Warshaw