I am under the impression that the 18 was built in the 14 body and so should be the same as the 14, I am sure Paul will correct me if I am wrong.
Also the MK27 we restored is gutted (no motor, batteries, etc ) and it still weighs a couple of hundred pounds but is very easy to handle except we don't have the rollars for the 27 and it doesn't work on the other rollars so I am going to have to make new rollars.
Tom