For a multitude of reasons, I've decided to ditch my XS ECU and get the PFC/datalogit. I've been reading like mad about the various EMS's, but I haven't come across much on the generics of tuning. Could you guys recommend some resources? Basically, I understand that you use a wideband to adjust your fuel, but timing really seems to be black magic that can have dire consequences. On top of that I've been reading that the PFC has a bit of a reputation for having too much advance at high rpm, so I'm afraid to just assume it will be all right as is.

I want to do this right, and my plans are to use the maps sent to me only to drive it to the dyno. I just don't fully understand what to do from there. I'll be taking others that have PFCs with me, but I'd rather know what I'm doing rather than totally rely on their knowledge to be accurate.

One other question. My XS is currently programmed for 12psi. But I plan to back that back down to 10 since I don't have an upgraded IC or radiator, and I'm still on the original stock turbos at 120k miles (and I want them to last as long as possible). But I'd still like to run 12 on autocross and track days. Does that mean you have to tune for both on the dyno?

Thanks a billion!