Excellent review as usual. Might not be completely scientific on a geek level but certainly illustrative, balanced and straightforward.
I think some folks in here are ignoring (or are completely ignorant of) the context of this particular review, which is AutoX competitiveness and effectiveness.
In a competitive autocross context it's no surprise at all that FI is a terrible idea for this car given the classification system. Going FI on a Toyobaru puts you straight into SM which is where the highly-to-extremely modified Evos, STis and M3s live on massive DOT slicks. Might be possible to build a competive SM Toyobaru in theory but it'd have to be a pretty extreme and creative build. Realistically there's a 99% chance you will just get your ass handed to you each and every time and that's that.
Breaking out of classification issues it's interestitng but not completely surprising to hear that there's not much of a competitive advantage to be had from going FI. I'd theorize that given a well set up car and an adept driver there would be at least a marginal (few tenths worth of a) performance advantage depending on the course layout. I'd concede that in reality (assuming a well set up chassis) getting tenths in Autocross is more about the driving though.
Pretty sure that things will be more pronounced on the track.
Great, thought provoking review again though. Thanks for that!