I'm well aware the Evo was built from an I type chassis.
What I was referring to was that UDN's demise led to Lionel starting the Evo project.
The insurance job replacement S chassis went to Andrew Dearing/Tony Favarin as far as I am aware, through Lionel, and that led on to Lionel acquiring the Evo I chassis. I'm pretty certain the replacement S chassis is not what we see under the GTO.
Lionel showed me his own photo album which showed his road car (probably contemporaneous with UDN) which certainly showed development firstly into a rally ar and then into a racecar.
He wrote all this down once I believe but given his propensity for rewriting history then anything could be true.