tm - if it works, probably an hour. If it doesn't, forever...
The problem is, as Heydu predicted, the ZZII is running SO many non-"normal" parts, and doesn't have the "normal" equivalents. I tried to graft on the Ruf RGT normal parts for the relevant components - according to the settings screen this has worked, but it isn't allowed to enter PD Cup or Trial Enduro.
The back-up plan is to basically get another standard road car and change the body, chassis, engine and settings to that of the stock ZZII. If you'd like me to do that, it'll take about 20 minutes.