As Jim mentioned...his old ITC was converted to prod...
Back in 1998 by a kid at the time...me. I sold the car to Bill and then he decided to run it in GT4. As Kevin says... If I was you I certainly would run it in HP as it is difficult to be competitive against the miatas and acuras etc. I ran in FP at the runoffs in 1999 and actually the car was moved to GP by the comp board the following year as the Datsun 510 and Rabbit were already moved there. In 1999 in FP the car was 1790 lbs..in GP it was 2090....where the added weight made us break off the rear axle hub ...2 out of 3 nationals in 2000. There are lots of cool things you can actually do and Bill retained a fair amount of what we did to the chassis, but he made it even better. The rear spindle can be modified and a bracket made to use front calipers and rotors on the rear. As it was difficult to fit coilovers in the rear, we instead added 5" spring bucket at the top of where the stock spring sits..then welded the wedge bolt nut..ran aluminum wedge bolt and birdcage..and welded a spring seat atop the rear axle to hold the 5" spring. Can scale the rear of car in a matter of seconds with a half inch drive. We used the BAT rally flares to cover the tires, but we still used 13x6 revolutions w/ 8" goodyear slicks, and then we blended in the rear flares with fiberglass matting. We utilized a formula ford oil pump and dry sump set up, titan roller rockers, and alternator cog. The oil pan on formula ford is different length..so we cut and re welded the stock one, this was done along with the engine and sidedraft webers by MWE marcovicci wenz engineering on Long Island.
You should definitely get the BAT billet front hubs if you already don't have them, with the added grip of the slicks...you will snap the stock ones..and it is always something you have to keep an eye on. The 4.06 final drive and Quaiffe are also must have for the Fiesta. If you can find the close ratio 3rd and 4th gearset that also helps. You can run pretty high spring rates in the rear along with an adjustable rear sway...do not run a bar on the front.

Anyway, its been a long time since i ran that Fiesta...and I still miss it...great little cars. If you need any help..feel free to shoot me a PM...as i still remember some if the little issues and how we resolved some of them.