I'm having a hard time waiting!! Just got my new Comfy Fit harness for my three year old, so that was this fall's investment but next spring I will be getting a Hyperbike!!
You do not need a special harness for the HyperBike. We do find that we need to let down the tug loops one notch from what we use for the easy entry. You might prefer shorter reins, and a shorter whip is nice, but that's all personal preference.