I saw one of these built as a displacement class car using a 1300 cc Alfa engine that put out close to 130 bhp Was one of the nicest sounding cars on the track. They were also the equivalent of what the Lotus 11 (or arguably 17 which was pretty much the same car) had been to front engined sports racers.
In the early-to-mid '80s in Northern. CA, a Lotus 23B named 'The Spoiler' powered by a hot-rod 215 Buick & a Porsche 911 transaxle was a top contender in the NCSCC series- a hotbed of club autocrossing at the time. Originally run by two guys and their wives, it was always a contender for TTOD against Formula Atlantics, modified big-block 'Vettes- anything. In a particularly open slalom held on the Lone Pine Indian Reservation, The Spoiler clocked 172+ mph and reportedly about scared its owner to death.... Sold & restored to a regular 23B, I've lost track of it.