Different IR emitters do put out different levels and different spread, just like any LED product.
But you are current limited on the outputs and there isn't going to be a night and day difference between different IR emitters. The blaster on the front of the URC base station is the most powerful IR output you can get with that setup.

Is there a reason you can't put the URC base station near the equipment and use the individual IR emitters on the equipment?