Amperage and MAH how is it doubled ?

[SpeedAssault]

I have done a lot of reading and have not seen a FAQ sticky on this.
I am very frustrated just trying to figure out what size lipo I NEED for my new project car. (Castle Monster combo 2200kv) 9 lbs car, 4WD, mostly street bashing speed runs and rally hard pack driving, speeds in 50's

The big problem is I read and hear different stories about Series and Parallel.

Hobby shop owner says if it's in Series "everything is doubled, including amperage
Another guy says if it's in parallel the MAH it's doubled.

For Example Two 3s 3000mah 30c lipo in series becomes 6s 6000 60c.
flip side Two 3s 3000 30c in parallel becomes 3s 6000 30c.

SO I ask you guys What is the true answer on this and where is the calculator to figure what continuous amperage do I need to run ?

Another confusing lipo issue is one lipo will say 30c at 67amps and another will say 30c at 81 amps.
I was told it depends on how many cells are in series or parallel in the battery. Problem is many batteries onle say C rating.


Castle creations told me they recomend that I run 33c for my setup. But what is the true amperage and if putting lipos in series is best then what C / amp do each batt. need?

Appreciate the help