Pretty sure the impulse came out before the Zante Pursuit and isn't being continued. Doesn't make much sense to replace a more recently discontinued shoe with an even longer ago discontinued shoe.
The Tempo is the Zante replacement.
I'd say live it up a little and go with something a bit more modern though. The Fuelcell Rebel is where to look if you want to stay in New Balance and want a 6mm drop and a faster shoe.
Performance/speed trainers:
Skechers Razor 3, Reebok Floatride Run Fast, Brooks Hyperion Tempo, Fuelcell Rebel.
Little more cushioned but lightweight trainers:
Saucony Freedom 3, Skechers Gorun 7+, Reebok Floatride Panthea, Pegasus Turbo 2.