Round 52 will be a re-roll of the Round 50 stats.
Beta stats contain the 'most accurate' stats, but only 2 real changes have been made so far:
swapping zik bs and etd cr fleets around
evening off the resource costs for pods [my personal preference]
I need to probably rebalance the fr/de and cr/bs a bit, and I'm also tempted to lose the Beetle T3.
I hope to update them over the next week or so; suggestions welcome