Limited Slip

[AHSprite78@xxxxxxx]

I've got a '96 328is without ASR or whatever they call traction control with 
all of that electronic stuff.  As far as I can tell it does not have a 
limited slip differential.  I'd really like to have one, as it would be nice 
for driving schools and autox and in the snow.  
How can I check to see if the car has it?  like the rearend and turn one 
wheel?  what's the other wheel suppost to do?  
Lets say the car does not have one.... where can I get one?  Should I go for 
a complete unit that would bolt right in?  Quaife limited slip?  
Any other recommendations?  

Thanks
Matt Smith
'96 328is

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