The frame or unibody (from shock tower to shock tower or “ladder” frame) is sacrosanct. These must stay intact unless otherwise allowed in these Rules.

1. Body, frame and sheet metal (such as transmission tunnel) may be altered to the minimum extent required to allow engine swaps, transmission swaps and suspension modifications.

2. Subframes may be replaced or modified.

3. Vehicle perimeter and wheelbase must be full-scale to original model. Incidental wheelbase and overall dimension changes resulting from the allowed replacement of suspension components or modification of suspension design are allowed. This is not an allowance to shorten or lengthen the chassis/body (e.g., change the scale from the original).