Rd16rr

just a random question here: driving along, fully warmed up....free flowing traffic at parkway speeds....and i'm getting an odor that seems to remind me of a catalytic converter getting hot...the first time it happened (at the one thousand mile mark) i thought it was a newer car just in front of me(a new beemer)...the next time it occurred....maybe 200 miles later, there were no new cars in sight, and it seems to engulf the cockpit for maybe 3+ miles with the top down (which leads me to believe it is my car) -- both outer exhaust tips are blackish in color after this ride