So I have a 94 GSR that had an engine that was burning crazy amounts of oil before I replaced the motor. It burned 4 quarts of oil on a trip from Texas to Colorado (about 1000 miles) just to give you an idea of how bad it was. To make things worse, it's white so it was just caked all over the rear so washing the car was a big PITA with the old motor. Now that I have a new motor in it I still see a little bit of oil residue on the rear bumper but I know the motor is not burning oil (because I'm f-in paranoid about checking it after having the old engine).
I can see a **** load of oil residue inside the exhaust tip (Greddy SP) from the old motor. There's so much I can actually scrape it out with a knife. I'm assuming it's just as bad through the rest of the exhaust system. Aside from replacing the entire exhaust...can you all think of any way to get rid of all that ****? It's not a problem, just bugs the **** out of me to see that residue on my bumper.

 

Could it be that you are running rich now? MAybe try replacing the O2 sensor (try a universal for a lot cheaper)