Not unless you also do something to richen the fuel mixture (Ducati Performance ECU, Power Commander, ...)
In fact, your bike will run leaner with a more open exhaust = less smelly.
If you get midpipes, I recommend not opening the air filter box - it will run too lean.
I also suggest getting it checked by a shop afterwards, to see if it needs the small adjustments possible on a stock fuel system (too lean = runs poorly and gets too hot)
Midpipes does wonders to the music
![Cool](http://ducatimonsterforum.org/Smileys/classic/cool.gif)