I have carried nearly everything into Brazil through GIG with never once a problem. I always encase the original packaging with some form of cheap luggage surrounding and use expanding foam insulation. I have never had even a question. A 50" plasma Samsung TV I did declare but was just waved through.
The immigration and customs processes are totally independent and you almost never show a passport to Customs.

Only by bringing in many bags and lots of TV's is their a potential problem from what I have seen. I am guessing about that because neither Mrs jb nor I have ever been stopped.