The tuner must ramin in the vehice to work, you don't tune your EEC, you intercept and change signals so to speak, at least this is my undersatanding.
You may or may not have to use it for bigger injectors, the MAF sampling tube should match the injectors, thus fooling the computer into thinking that the injectors are stock.
If you have done any modifications, or boltons, it is probably necessary to get the car tunned for optimum and even a safe A/F ratio.
If your only mods are the ones listed in your sig lines, you probably don't need bigger injectors yet. Either way, your MAF will have to be calibrated for the new injectors.
In my opinion, an eec tuner is worthless without a dyno tune, or a wideband O2 meter. I have the eec tuner and a PLX datalogging wideband O2 meter. I am in the middle of installing the eec tuner and wideband kit actually. I'm swapping dashes, and tapping into various signals, such as TPS, RPM, MAF, ACT, and such. This way I can monitor and log several things to indicate what I will need to tune. The A/F will can be adjusted by several functions of the tuner, tweaking the MAF function, among other things, will allow you to tune into a flat (and safe) A/f mitxture. The eec tuner can also change fan on and off points, as well as idle RPM, and some other stuff I prolly don't know about.
I am in the learning process myself, and some of the guys here are happy to help teach you to use it.
The other option, if you are not planning other mods, is to get a custom chip burned for you so you don't have to worry with it. Just keep in mind, every time you change something, it will likely need retuning.
There is also an SCT tunner available, which folks seem to like better and is spose to be easlier to tune, but I got my eec tuner in a package deal with some other stuff, so I went that route.
The wideband will allow me to tune without having to go pay the dyno tuner every time I make a modification.
See xr7 Dave for custom dyno tunning chips, he is actually having a tunning day in St. Louis (I think he said) sometime in the near future.
Hope this helps!