I personally think the T/C in the evo is ****. What could I do to make it stronger and better? I have that horrible whining noise. Any way to rebuild before it is totally useless? Would adding a LSD to my current one or a new T/C help. What does a LSD help? I'm talking about street use.

 

LSD = Limited Slip Differential
It helps with cornering and controls the amount of slip (speed difference) between the left and right wheels. I don't think it would do anything to help you TC issues....
How do you get the TC is crap?
Try running OEM oils in the TC. A little bit of tranny whine is expected in the EVO ....