I know there are multiple topics like this, and I posted in them but never got an answer. And this exhaust is getting installed in an hour.
You may lock it after I get my answer.

My box did not include a new gasket that everyone has talked about, there is not even a mention of it in the directions. Will I be ok if I leave the oem one on there, or should I wait till I get a new gasket. Thanks.

you can leave the stock "donut" on. :)

Heres another q, I installed it , but the pipe is not centered at the back where the groove in the body is.

You bumped,
I answered.

http://www.scionlife.com/forums/viewtopic.php?p=1936566#1936566

Here is where my exhaust hangs if i mess with it.
http://i49.photobucket.com/albums/f279/i007spectre/Exhaustafter2.jpg
thats correct.

After driving a while it looks like this.
http://i49.photobucket.com/albums/f279/i007spectre/Off-centeredexhaust.jpg
thats wrong.

really hard to know what's really goin on without seeing the underside, but yeah that is a problem, cuz in the future the bumper might get a bit scorched in the long run.

I couldn't get the exhaust to fit right using the stock gasket, far too thick so it messed with the alignment of the system, that could be your issue. Mine did however come with a gasket, thinner so the exhaust fits correctly and just requires a little adjustment to get it straight initially.

so i should call injen and ask them to send me a gasket, thanks.

belive it or not i think i blew my gaskit that came with the injen exhaust, now it whistles all the time i dono what to do now, back to the topic i had the same problem i just hammered the hanger a little and it hangs low and doesnt move, good luck with yours