Couple Questions- C Rating, New LiPo Packs, etc.

[rawfuls]

Well first, destroyed my first pair of LiPos today, was quite amusing!

Anyways, now for my questions.

I'm running an ESavage w/ a Medusa 50-3300kV off of a Mamba Max ESC with 2S packs in series.

Also running an EMaxx w/ KD970 (Conversion Kit, KershawDesigns.net, not sold anymore, and actually is for sale ) on a EVX-1 with 2S packs.

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Will I be able to push these trucks with 20C packs?
Cheapest is best!

I know the higher, the better, the safer, but just wondering, is 20C pushing it?
20C 5000mAh 2S packs are like $15 bucks!