anyone else notice the guys who post from australia are always angry.

anyway OP, you can install a header back exhaust and get away without a tune. (i did for 30k miles with 0 issues). I had planned to get my header installed by my tuner so i could do a before and after comparison on the same day, same fuel etc... as others have said you probably won't blow up, but you'll be missing out on the true potential to your mods.