I vote for the catback.
If all I'm going to get is an extra 10 ponies with a complete system which looks like it's gonna cost some serious $$$, then I'd rather drop a few hundred on a catback and gain 3-4hp(?), and at that price go for the T409 and replace if/when necessary.

However, I'm only one customer.
As we've seen from the past...
If TVT will build it, then we will buy it.
Keep up the good work Anthony.