Don't mean to be rude, but this is the 3-D forum and there are one, maybe two models (maybe five or six) between a Nexstar and a 3-D capable model - and those might ought be a stik variant or a low-wing aerobatic model. Several variations and makes to choose from, but I can't think of a "good" 3-D model that would make a good choice for a second model.

You can kill a 3-D model in a power dive just from control surface turbulance and you have to fly two seconds ahead of them at all times. Hardly a good training tool for "smooth" aerobatics. 3-D is a step beyond what is normally considered fully aerobatic (Aresti patterns, at least).