Welcome to the site first off.
Next, to your question.
ANYTHING you do to alter the stock system,
is gonna cost you money.
You MAY get away with drilling 1/4" holes in the end of your pipe
with just a 12 minute tune, for a little while.
I did that myself, found my check engine light wouldn't go off.
I was running lean, plus the sound wasn't significantly much more.
Basically I screwed up a set of pipes.
Your best bet is to get the TORS and a factory tune for it.
It'll be louder, noticeably, and thats all you need.
Now, if on the other hand you end up doing more mods in the future,
which we all do, then you can probably sell your TORS right here
and recoup some of your money then.
Good luck, post pics, and again,
Welcome to the site.