Header installation questions

First of all, thank you for all of your posts. I have been reading threads here for a while. My truck is finally paid for and out of warranty, so it's time to play!

I plan to install a set of Pacesetter headers (yes, I'm on a budget) with no cats, Flowmaster 40 series, and dual echo tips exiting the rear, and a cold air intake soon. What else do I need to be concerned with?

Will I need to "tune" for A/F ratio concerns? For the secondary O2 sensors, I found a relatively cheap universal dual output sim. (Universal o2 simulator dual output [unv-o2sim2] - $40.00 : O2 Simulator, E-commerce) Will this work to remove on a Titan? If not, can someone give me advice on where to get a good deal. I don't care to solder resistors to make my on.

Thanks in advance for any help.