hyper black steering servo

[Dickylew]

Just got a hyper st black edition for my son and me for xmas.
Ive heard that the steering servo packs up as its not up too the job,if this is the case surley manufacturers have a duty to make sure they are fit for the purpose?
I'm new to nitro rc and would welcome advice on a replacement servo should it be needed but not too expensive mainly for bashing possibly local club use.
Would it also be advisable to use a 6v hump pack instead of the standard batt box, would this give a bit more power to the servo?
Any advise would be appreciated.