Balancing this will be no problem at all, and it's definitely on the right track.
I'd add a few more sharp edges and points to the beast like the original had - definitely keep the pointed cockpit. The surfaces on the top central section are too flat too, maybe try adding some miniature fins or something (maybe at the currently inset areas with the internal engine looking bits are)
My only major concern with the model is where are the torp mounts going to go? On the original model, they were on those big inset areas which I assume the hexagonal intakes are supposed to represent. I'm also assuming you want those to be actual intakes instead of torpedo mounts. Just something to consider.
Looking forward to V2. Also, if you're going to be doing more models for Discovery, you should probably PM me your Skype details.
