Can I make a playermodel with multiple primitives?

[KommissarReb]

I'm making a model in XSI 7.5 and made a weapon made up of multiple primitives instead of one big shape. But now I'm wondering if I should make all of my future models out of one big shape out of fear the game will lag if it has to draw all of those shapes in game. I read Bamdur's tutorial which helped me realize I needed things like dummyroots to get the models working, but I'm not sure what the best and easiest way to make custom models is.

Could I get away with making models out of multiple shapes, or do you recommend something else? I also don't know how you take a single .tga full of mix-mashed textures and know how to properly apply that to a model.