I don't believe that you'll pass emissions with an EGR blockoff. An EGR blockoff will exhaust gas from entering into your intake tract, thus lowering your temps and also help reduce carbon buildup in your intake manifold. However, it does not effect your performance a great deal. I've heard this theory; I'm not sure if it's entirely true:

If your turboed (which I'm certain you are), you could have a long term problem with your valve seals. The EGR acts as a link between the exhaust and intake tract. Sort of equalizing the two pressures. Over time, since there's a relatively large difference between the two pressures, your valve seals may become damaged.

If I were you, I'd just put a catch can in. Best of both worlds.