I must be a dope. I don't follow what the the problem is with downshifting. It's probably the simplest part of driving a stick shift vehicle.
CamK18, if you downshift with the revs too high, the engine will aggressively gear down. If you pop the clutch when downshifting (releasing the clutch pedal too fast) it may jerk, and if the revs are too high you will also chirp the tires.
Try lowering the revs before downshifting from 3rd to 2nd. If you're going too fast it usually won't let you put in second gear anyway.
1968 Camaro convertible, soon to be LS1 & T56, Magnaflows, 3.42 posi, 17" Torque Thrusts
2011 2SS/RS, LS3, M6, IOM in and out, factory Hurst short throw, GMPP axleback exhaust