I looked into using a GC engine from a K11 Micra in a RWD and it could be done. There's the CG10DE, CG13DE and CGA3DE but the first two have a distributor of the back of the head. The CGA3DE doesnt' so no clearance problems on the firewall and from what I could see the gearbox bolt pattern was the same as a GA series engine. The C23 Serena came with a GA16DE mounted inline/RWD so there's a gearbox that would work. I wonder if the CR engine shares the same gearbox bolt pattern as the CG before it?