I have its cousin, the EEC Tuner, and I think it's great, it lets you maximize whatever combo you happen to have, but the learning curve is steep, and you need to get a WideBand 02 to fully make use of it.
Taking a look at your sig, if that what your car has right now then you won't be able to do much with the Tweecer/EEC Tuner.
I assume you have a Calibrated MAF for your 24lb Injectors, unless you've tuned it mechanically(with a FPR) or already have a Custom Chip, most likely you're running richer than you should. Tweecer can take care of that.
I love my EEC Tuner primarily because the T4M0 (SN95 EEC) is severly crippled, and instead of having to replace the whole harness and stick in a A9L, I can just run the A9L Program as if it were stock
Even though my mods aren't many yet, I can feel a huge difference, and when I get the stuff I have coming (Heads, Intake, Rockers, and WB02) oh man, I am going to be able to pull out every last horse out of my humble setup