I have been a passenger in a slightly modded FoST, cooling and I believe some brake work were the main things done to the Octane cars where the FiST was stock. A very fast Vette racer I know that owns a NASA championship car, instructor at the track, he was flying in the FoST, far faster than I imagined it could be, I was quite impressed.
After driving both cars during the days events I found I liked both a great deal but the FiST put more of a smile on my face every time, I picked it for the hot lap session and had a blast in it and was complemented on my speed. I picked it because it was more fun and I was bringing out my highly modded FiST soon for a two day event and wanted a bit of track time in a similar car.
Nearly all if not all the instructors said they liked the FiST better, just more fun to drive, I did not even ask about lap times. The head of the Ford race shop that takes care of dozens of cars loves the FiST, likes it better than the FoST as well.
FoST has better rear suspension, wider track and lower center of gravity and more power.
FiST has a livelier chassis, higher CG and less weight. (I removed some of the liveliness of the chassis for safer/faster lap times in my highly modded car)
Both are really fun cars to drive at speed, FoST would make a better family car, FiST more engaging, not a huge difference in performance so one can be modded to be faster than the other fairly easily or left stock depending on what one likes.
I think we are just damn lucky to have two such great cars to pick from
Rick
I prefer the lighter car, always have, then mod to my taste which we all should do.
Which one is ultimately better is your choice, they are just different, buy one and roll your own mod list into it, or not, have fun