IMG - Photo by Jeannette Greenhaus

Car Classing

IMG uses a car classing system known as the Performance Index, which matches cars of similar capabilities and lap times together for close, competitive racing. If your car is already built for an existing racing or time trial class, use the class equivalency table below to quickly and easily identify your IMG performance index.

Class Equivalency Table

Most existing racing and time trial classes map to an IMG Performance Index class. Use the table below to find out where your race or time trial car fits in our classing system:

If your car is not currently classed in a particular class or is not listed in the table below, use the Custom Car Classification Form.


NASA German Touring Series U (GTSU)
NASA Super Touring (ST)
NASA Time Trial 1 (TT1)
NASA Time Trial 2 (TT2)
PCA '06-'09 997 Cup (GTC4)
PCA '10+ 997 Cup (GTC5)
PCA 993 Cup (GTC2)
PCA 996 Cup (GTC3)


NASA American Iron Extreme (AIX)
NASA German Touring Series 5 (GTS5)
NASA Performance Touring A (PTA)
NASA Time Trial 3 (TT3)
Spec Cars Thunder Roadster (TR)


NASA American Iron (AI)
NASA German Touring Series 4 (GTS4)
NASA Honda Challenge 1 (HC1)
NASA Performance Touring B (PTB)
NASA Time Trial B (TTB)
PCA 944 SuperCup
PCA H Stock / Prepared (H)
PCA I Stock / Prepared (I)
PCA J Stock / Prepared (J)
Pro Truck Pro Truck
SCCA American Sedan (AS)
SCCA E Production (EP)
SCCA Touring 1 (T1)
Spec Cars Panoz GTRA


NASA Camaro-Mustang Challenge (CMC)
NASA Honda Challenge 2 (HC2)
NASA Performance Touring C (PTC)
NASA Time Trial C (TTC)
PCA E Stock / Prepared (E)
PCA F Stock / Prepared (F)
PCA G Stock / Prepared (G)
SCCA F Production (FP)
SCCA Improved Touring R (ITR)
SCCA Spec MX-5 (SM5)
SCCA Touring 2 (T2)
Spec Cars Factory Five Roadster (FFR)
Spec Cars Legends Car (LC)


BMWCCA M3 Touring (M3T)
BMWCCA Spec E36 (SE36)
NASA German Touring Series 2 (GTS2)
NASA Honda Challenge 3 (HC3)
NASA Performace Touring D (PTD)
NASA Time Trial D (TTD)
PCA D Stock / Prepared (D)
PCA Spec Boxster (SPB)
SCCA Improved Touring S (ITS)
SCCA Spec Racer Ford (SRF)
SCCA Touring 3 (T3)


NASA German Touring Series 1 (GTS1)
NASA Honda Challenge 4 (HC4)
NASA Performance Touring E (PTE)
NASA Spec E30 (SE30)
NASA Time Trial E (TTE)
PCA 944 Cup
PCA C Stock / Prepared (C)
SCCA Improved Touring A (ITA)
SCCA Showroom Stock B (SSB)
Spec Cars Entropy Sports Racer (ESR)


NASA Honda Challenge 5 (HC5)
NASA Performance Touring F (PTF)
NASA Time Trial F (TTF)
PCA B Stock / Prepared (B)
SCCA Improved Touring B (ITB)
SCCA Showroom Spec Miata (SSM)
SCCA Showroom Stock C (SSC)
SCCA Spec Miata (SM)
SCCA Spec RX7 (SRX7)
SCCA Touring 4 (T4)


PCA A Stock / Prepared (A)
SCCA Improved Touring C (ITC)


NASA German Touring Series 3 (GTS3)

Can't find your car class, or is your car not classed? Click here


If you have any questions about classing your car, feel free to email us at