You are forgetting key elements to your statement. These elements are that these cars are modified from their STOCK configurations. If they are in professional races, there are homolgomation rules that the manufacturer has to follow in order for their "modified" cars to compete. That is why there are "limited production" series vehicles.
Kick which Esprit's arse? 4cyl or 8cyl? I seriously doubt that a stock STi can beat me in my stock V8 Esprit. I definitely know, because I used to work for Subaru of America and have done plenty of "comparison testing" of this Vehicle. The US market gets a 300bhp version of the STi, but it is still weighs more than my Esprit. If we're going to compare vehicles, let's compare apples to apples. Any trim level above the base model (they have to have the same motor; i.e. STi, STi RS) of these cars I consider a modified series.
If you want to compare modified vehicles, let's compare them to Johan's Esprit..