Greetings All... I'm the original owner/builder of the Orange S1 #50, that you are talking about. I drove the Yellow S1 that used to be Dean Rosen's, no comparison. His engine had a mild cam, and the Webcon set-up, and an aluminum flywheel. That's about it. Mine had High Compression Forged pistons, H-Beam rods, Rally Cams, Ford Racing Head, Light Aliminum Flywheel, Rally/Race Trasmission, and most important, Pectel ECU. The Webcon sucks. If you have one, get rid of it. It will make the biggest improvement in your car. I also added a MAP sensor, by machining the intake runners, tied them together, and intalled the sensor. That added a drivability to the car that blew me away.
As far as your cold idle problems go, check your voltage on the TPS, Water Temp, and have a MAP sensor installed. Ditch the Webcon.
By the Way... Dean's old Yellow car has WAY over exaggerated HP/Torque numbers. I have copies of all the Dyno runs for my old Orange S1 (best one on the planet).
Get to a good tuner shop, and ask then what ECU they recommend. Let them install and tune on a Mustang Dyno (not DynoJet). That allows tunability at different loads.
