the Improved Production rules seem to be much more restrictive than NZ's SS200.

We have to retain all steel panels, and cannot cut the supports under bonnets etc. No-one said you have to use every bolt to hold the gaurds on though... Cannot even cut radiator support panels to suit bigger radiators! steel bumpers must remain (if they were originally steel) and their mounting brackets cannot be modified. There are only a few areas where metal removal or even reshaping is allowed.

All glass must remain, all lights operable, window winders, door locks etc all must remain. Same with wipers. heaters can be removed though. Dash must remain and any openings (from removed radios, heater controls, glovebox etc) must be covered. Interior trim below windows must remain, excluding floor coverings.

Springs must be of the same type (ie coil or leaf) and remain in the same location as standard, but are otherwise free. There was some talk here in the past of fibreglass leafs from the US... Struts and brakes are basically free. Steering must be from one variant of the model (some cars have optional power steering for example), so we're stuck with the steering box.

that's the short version I guess...