Thunder-power 30 or 45c cells ?
 

Are the new thunderpower 5000mah 30 or 45c cells good enough for the savage flux ?

30C is more than enough, 45C is just overkill!

No such thing as over kill. the 30C will net around 150amps continous which is over the recommended 125amps from HPI and Castle. While the 45C will give you major breathing room at 225amps! This is also important especially if your pushing 6S Keep in mind, that the larger the breathing room for your amp draw, the less harder it is for the battery keep up with the current load. That will extend the life of your batteries as well as reduce stress on your ESC, which has been the major cause of ESC melting, batteries that can't keep up with the current load from the ESC = smoke and sad feelings

For lipo batteries and ESC's, theres no such thing has having "too much" rated discharge

When on 6s Lipo, Internal Resistance is more important than C rating

True, but they tend to go hand-in-hand. Low resistance = higher C rating.

the really high c rated packs have an additive in them that raises the c rating, but at the sacrifice of longevity. they don't usually live as long as 30c packs.

The 45C G4 packs are advertised as having much longer cycle life than the older versions.

So If I had a esc, and the #'s below are the info for it, if I bought a TP 6s 45c lipo, could the speed control handle it? If so, is there a limit on the Mah I should use?
Number of Li-Ion, Li-Pol feeding cells 2 - 6
Operating voltage 6 - 25.5 V
Max. continuous current (for full throttle) 280 A
Max. peak current (peak 5 sec.) 340 A

The mah of the pack is only going to be limited by the room on your chassis and the money in your wallet! I would make sure it's over 4000mah

5000mah 25C minimum is recommended for the Savage Flux. I personally use 5000mah 30C or higher (40-50C is great). The higher the C rating the better as C rating determines the resistance of the lipo cell, and thus determines several other factors mainly the voltage under load of the pack for a given amperage, and the temperature the cells will come out at after the run. The higher C rated batteries are able to be charged at a higher C rate, but this can shorten the longevity of the pack so it's still generally a good idea to charge at the 1C charge rate you always have to ensure you get the most out of your packs.