Exhaust fumes in the truck

[pumpkin]

I was just wondering if anyone has problems with getting exhaust fumes in the truck at any time. Top on,, top off,, back window open? And where does your exhaust exit, if you do have exhaust getting in? I'm am tying to figure out where to put my tailpipes. I originally had it coming out the side just in front of the rear tires, and had no problem ever, but seem to remember on my other Blazer, at times there was fumes getting in. Its tail pipes where out the back.