Children or Triangles

Does anyone have experience with this....

I am building a model, it's going to be approx 5000 tris.

There are 250 pieces in the model, that are glued together as children. With in the modeling program Truespace, I can Boolean Add these together to form one complete model...But when I do that, TrueSpace and Blitz Reports a lot more triangles. So my question is this... Would an Object with 250 children be more GPU intensive than a model that has more Triangles.

First off, reducing the surface count has a HUGE benefit for performance. And each child object is its own surface. Thus, merging everything together into a single object/surface at the cost of additional polygons is a smart tradeoff.

Second, avoid booleans. Booleans are evil! They do all kinds of nasty things to your models, like lots of tiny splinter polygons and cracks in the mesh. Just say no. I'm sure Truespace has some sort of combine/merge function for putting together multiple meshes into a single object WITHOUT doing any sort of boolean operation. I've not tried in Truespace specifically, but every modeling tool I've used has a function like that.