I don't even think you need a normal + spec map. I mean, if the sink is solid, smooth porcelain, there's no benefit. The normals and specularity are consistent.
I think the model's fine. The only thing you need to tweak is the lighting. Try something like a three-point setup. Have a strong spot-light on the front of the model, a weak lamp hovering over it, and a weak spot on the back (and slightly off to the side). Make it so that the strong spot is the only one to cast shadows, and that the other two do not cause specular reflections.
There aren't a whole lot of places on the model that would benefit from AO, but if you want to add it, for these purposes, I recommend using an approximate calculation as opposed to raytracing. For a simple scene like this, you can safely trade accuracy for faster render times. Also, be sure to set the Pixel Cache option on.
Hope that helps
Edit: Also, your materials look very default. The bowl should have a much harder specular reflection (to look like porcelain), and the faucet should reflect more with a slightly harder reflection.
Edit 2: I can't believe I just spouted all of this without knowing what you're using this for.
Are you doing this as modelling/texturing/lighting/rendering practice? If not, ignore everything I just said because the renders won't matter if you're going to export it to somewhere else. Sorry 'bout that