have you reset your ecu? sometimes something that simple will help.
if its running super rich and blowing black smoke maybe you have a fuel issue, leaky injector or something like that.
is it throwing any codes? even if it isnt take it to autozone and have them check anyways, sometimes the ecu will have a code stored but not trigger a cel.
if the ecu reset doesnt work and there are no codes id take it to a shop and let them look at it.
you might have gotten a lemen turbo, that would suck. check the bcs it might be weird too, the subaru bcs is retarded, its right above the airbox.
02 rex is gone.
I defected to an evo :)
Evo is gone :(
Now I got nothing.