I have an '03 Cobra and I say congrats. If you win, you win. As long as you win fairly (no fly-by, etc.).
It's likely you ran an '03 that had cat backs only, since most '03 owners install just that...cat backs don't void the warranty. Everyone's paranoid of voiding the warranty...the motor's really durable but it costs $13k to replace.
Then you get bored and say screw it all and start modding
That said, watch out, cause it takes less than $1800 to get an '03 Cobra running 11s.