Hey guys,
My 1991 MR2 Turbo seems to have a sh*tload of carbon in the exhaust. 
So much that when I rev the car up pieces of black carbon shoot out the back onto the ground. 
The car also puffs some smoke when revved up (Black Smoke).
I am replacing the turbo seals and all the bearings today.
If that doesn't work, does anyone else have/had this issue?
Cheers!

Sounds as tho it is running quite rich
Probably normal for a turbo
What work has been done to it?

Carbon not serviced often enough?
Have you tried an up engine foam cleaner and a good engine flush/detox
Liqui moly make a great one
Run it for 20 mins
Dump oil replace oil filter re full with good synthetic
May help :)

As above, sounds like its running rich.  They run rich on the stock tune under boost as it is safe, so that is quite normal.  I wouldnt think it is anything to do with turbo seals etc, if it was blue smoke than that generally indicates burning oil, but black smoke generally means just running rich.
 
How is your oxygen sensor?  A dud/unplugged oxygen sensor can also make it run rich.  Air filter clean?  How is your fuel consumption?
 
Other things that can cause it to run rich is dodgy ecu water temp sensor and AFM.
 
Cheers