Three other unique R90Cs were cars that were based on existing cars but modified. One R89C was upgraded to become an R90CP, originally used by Nissan in the JSPC before all cars were completed. Nova Engineering purchased chassis #07 from Lola and initiated their own upgrades to the chassis, calling the car a R91CK. The final modified car was an R90CP bought by Team Le Mans and modified into what they termed the R91VP. Both cars featured minor aerodynamic differences from the other R90CKs and R90CPs.