I just took my turbos off and found a crack between the waste-gate and I believe the exhaust outlet. I was getting a boost leak and tons of smoke on initial startup. Would this be the only cause? What would a crack like this one do to a car? Please let me know ASAP if anyone has any info on this subject.

 

I think a crack in that location will spool the secondary more than normal. You can probably still run in non-sequential mode for a while with new gaskets, but this isn't something you want to drive around on for a few years. Depends how big the crack is too, I (and most people) have little cracks in various places, but my turbos run A-OK.
~Tom

 

This is no small hair line crack. It is approx a 1/4 inch wide.

 

And it goes all the way between the openings? like...there's metal missing? You'll still be able to run, won't cause boost leak or smoke, but you'll be better off getting a new piece of iron or having it welded back up. But cracking in that location is normal, happens to everyone. judge for yourself.
~Tom