Lipo C ratings

[Cardnim]

Hi guys,
My old battery puffed up and is now useless, so I have now only one Lipo left so I am going to buy another.
But before I do, is the C rating important?

My old batt:
7.4v
5400mAH
45C

My new batt:
7.4v
5000mAH
55C

Was my car jsut too powerful for the old 45C and therefore it puffed up and went bang? If so, then I dont want to waste my money, buy a new battery and have the same thing happen.

My problem is you see that I need a lipo battery with "feet" on the hardcase, and the only ones Speed Power (the company I want to use) do with feet are 45C.
Do I need to get 55C batteries?

Thanks!