as the you already said the TRD
only give a 1" drop...which means the spring rates really aren't all that different...which means your otherwise stock suspension components will work pretty good for at least a few years. when you start dropping over an inch its a good idea to get new shocks (just fyi)
you do have an '00 though..how many miles have you put on it? if your already around 80k or so you might want to consider putting some shocks in but that also depends on how the roads are around where you live and your driving style as well.