Originally Posted by tabetha

I could tell you of people who have this and don't even get through emisssions, but they want to remain anon, that is thier choice and I have to respect it.
You will get better economy and emissions with a decent map session, but of course it has to be someone who can map the system you have.
I don't use the oe system,(as not a fan), but would personally trot over to NMS if it were my money.
I get when driving easy 350+ to a tank from my 2wd cossie, with 150,000+ miles on it, and it does regular dyno sessions all day long some days, 4 hours last monday for example.
Idle co is less than 1% and PERFECT as the igntion alters to suit and keep the idle stable, I have the capability to run CL and have the gear all wired up, it is ONLY a press of a keyboard button to do it, which I can do from my laptop in 5 minutes, but I don't, need to.
Depending on target afr set it can limit power and limit mpg, proper setting up/mapping will give you the best of both worlds.
The car can only be as good as it's components allow it, one of the reason I changed my ecu, you CAN get excellent results with the oe ecu, but you can also get more features, use from a aftermarket one, I have my fave, and he is about 1/4 mile away.
The resason I chose my ecu maker was because of that he makes them, he designed it too, so you get to speak to the people who know it better than anyone else.
Another point was future safeguard whenoe sensors are hard to get, I canuse any and calibrate myself simply free and easily.
tabetha