I’m currently trying to build one of these- but in a very atypical fashion.
The plan is to try and find a blown up GT, and replace the drivetrain with a Duratec 2.5 (fusion) and transmission from a NC miata. The little 2.5 is good for 200ish wheel HP with some work, and a 4.30 gear will put the ratio pretty much exactly the same as an NC miata (because of the taller tire, but I’m leaning toward a 4.56 to better deal with the weight difference and to put it in the 4-6k range in 3rd gear at autocross speeds).
While it won’t BE fast, keeping the little 4cyl spun up and happy should make it pretty entertaining. I figure it should be about as quick as a v6 car, but with a hundred or so pounds less on the nose.
The goal is to build something I can take to the autocross, flog all day, and drive home without breaking anything. Having way more tire (the plan is 275 square) and brakes than the 4cyl (and my mediocre driving skills) can take full advantage of should also keep the consumable somewhat in check (I hope… maybe).
EDIT- for the people that are going to say “just buy a NC miata and swap it” I’m 6’9" tall, I don’t fit in a miata. A mustang is about the smallest car I can fit into with a helmet on, and the seat has to be relocated for that to happen lol.
