if your getting serious i would consider a wideband and getting the car tuned....
your s trim kit should have come with the BTM box,and FMU, if you want to run untuned the FMU should give you the extra fuel and you have control of ignition retard....
keep her a little fat and be modest on the timing and it should be alright... but a tune would make the car drive better and have more power.
i started tuning my car with a a tweecer and have had nothing but good come from it, better drivabilty, power and etc, still working on things but its 100x better than when i ran the car untuned...