To determine what changes move cars between S, P, I and M classes see the complete PCA classing rules.
The complete PCA classing rules can be found in the 2017 PCA-Parade Competition Rules:
PCA 2017 Parade Competition Rules. (Not yet updated for 2018.) Autocross rules are on pages 15-30. Small Region classifications are on page 28. We use a modified version of those classifications, as listed below.

Porsche Classes
Oregon Region PCA Autocross runs under a modified version of the small region rules. Be sure to check the allowed modifications section in the Parade Competition Rules if you have made ANY changes (including R tires or larger tire sizes) to your stock vehicle. The intent of the Showroom Stock class (S01, S02, S03, & S04) is to create a class for automobiles as normally delivered and specified for use in the United States and Canada. Factory options as normally delivered for a specific model year are permitted. However, anything beyond this, especially anything that could be reasonably perceived as being performance affecting would not be allowed in Showroom Stock. For example, Automobiles must run with their spare tire, jack, lug wrench, owner’s manual(s), tools, etc. Cars running out of class will not receive Championship Points. If you have questions contact your Autocross Chairman prior to the event at:

S01  968 (All), 911 Carrera 2 (964:1990-1994), Carrera 4 (964:1989-1994), RS America (1993-1994), 911 Carrera (993:1995-1998), Boxster (986:1997-2004), Cayenne (2003-On), Macan (except turbo) and Panamera (except turbo)

S02   911C2 Turbo (965: 1991-1994), 911 Carrera (996:1999-2005), 911 Carrera 4 (996:1999-2005), 911 Carrera (997:2005-On), 997S except X51 (2005-2009), Boxster S (986:2000-2004), Boxster (987:2005-On), 718 base Boxster/Cayman, Cayman (2006-On), Cayenne Turbo, Macan Turbo and Panamera Turbo

S03  911 Carrera (991), 993 Turbo (All), 996 Turbo (Non-GT2), 997S X51 (2007- 2009), 997S/GTS (2010-On), Boxster S (987:2005-On), Boxster S (981: 2013-On), 718 Boxster S/Cayman S, Cayman S (2006-On), Cayman R, Boxster GTS (981- 2014-On), Cayman GTS (2015-On)

S04   All GT2, GT3 and GT4, 997 and 991 Turbo/Turbo S, All 991 Carrera S, 991 Carrera GTS, Boxster Spyder (2016 on)

P01  356 (All), 912/912E (All), 914/4 (All), 914/6 (All), 924 (All), 924S (all), 924 Turbo (931: All), 944, (All), 944S (All), 944S2 (All), 944 Turbo (951: All), 928 (All), 911 (1965-1969), 911 (1970-1977), 911 SC, (1978-1983),  Cayenne (2003- On), Macan (2015-On), Panamera (2010- On)

P02  968 (All), 911 Carrera 3.2 (1984-1989), 911 Speedster (1989), 911 Carrera 2 (964:1990-1994), Carrera 4 (964:1989-1994), RS America (1993-1994), 911 Carrera, Carrera S, C4S (993: All), 911 Carrera (996:1999-2004), 911 Carrera 4 (996:1999-2005), Boxster (986:1997-2004),  Boxster S (986:2000-2004), Boxster (987: 2005-On), Cayman (2006-On)

P03   911C2 Turbo (965: 1991-1994), 993 Turbo (All), 996 Turbo (Non-GT2), 997 (2005-On), 997S (2005-2009), 911 Carrera GTS (991: 2015-On),  997S X51 (2007-2009), 997S/GTS (2010-On), 996 GT2/GT3 (2002- 2005), 997 GT2/GT3/GT3RS (2005-On), 997,991 Turbo/Turbo S (All), Carrera GT (980:2004-On), Boxster S (987 S:2005-On), Boxster GTS (981-2014-On), Boxster Spyder (2016 on) All, Cayman S (2006-On), Cayman R, Cayman GTS (2015-On), Cayman GT4 (2016 on) All

I01  All air cooled and pre 1997 water cooled Porsches with Improved category modifications as listed on pages 22-23 of the 2017 PCRs (Parade Competition Rules)

I02  Improved Porsches that are water cooled and manufactured 1997 or later.

M01 All Porsches with Modified category modifications as listed on page 23 of the 2017 PCRs (Parade Competition Rules)

Notes on Non-Porsche (NP) Classes

  • A Porsche with a non-Porsche engine is regarded as a Non-Porsche.
  • NP and NPA Street/Stock class automobiles must meet SCCA Street class rules.  This allows cars to have some non factory modifications including one aftermarket sway bar, aftermarket shocks, exhaust and larger tires and wheels than stock.
  • All Non-Porsche cars on R compound tires are in the Modified class.

NP  Non-Porsche Front or Rear Wheel Drive Street/Stock class automobiles. Tires must be Uniform Tire Quality Grading System (UTQG) 200 or above.

NPA  Non-Porsche All Wheel Drive Street/Stock class automobiles. Tires must be Uniform Tire Quality Grading System (UTQG) 200 or above.

NPM  All Non-Porsche Modified class automobiles. This class will include any modification beyond those listed above and allows any tires including R compounds.