Impulse??

[MNBen]

What are the differences between an Impulse and a Synergy. When I bought my impulse earlier this year I shot them both and they felt and shot very similar. I went with the Impulse because of the color. I love it but wanted to hear from some experts on if there is any true performance differences. They both had the K8 cams and identical limbs and risors. Like I said the only difference I saw and felt was the color. I'm just curious because you never hear anyone talk about the impulse.
Thanks