b4 spinning round mid corner

[xray011]

I've ran my b4 with no real problems,that is till i rebiult the diff.
i re done it 4 times now and still have to run it tight to stop the screaming.The last time i did notice that the diff spring is flat(no bounce).
can this cause the screaming?
Also when i turn left the buggy spins on its self but runs wide when i turn right.The left to right turning circle is the same at slow speeds.
So what i am asking is.
will the spring make it sceam?
will the tight diff make the left to right turning different?
or is there some other reason that im missing?
setup is pretty standard
front blue 35w
rear silver 30w
Please help
Alan