Originally Posted by Ruiner
I said DEPENDING ON CLASS when I made my statement. *sigh* If weight is a concern, then AWD is out. That's common sense.
In 1995, Audi was banned from BTCC because the Audi Quattro was unbeatable.
In 1989, Audi was basically banned from the SCCA Trans Am series (If I remember correctly, AWD was banned). Audi dominated the 1988 TA series despite rule change(s) during the season that reduced Audi's horsepower. Note: Audi came into the season with less horsepower and more weight than (most) of their competitors.
From quick googleing, it appears that AWD is banned in many racing series (from what I can tell: American Le Mans, Grand Am, GTS and every open wheel series) because it is considered an "unfair advantage".
In the series where AWD is allowed, there is usually a significant weight penalty and many times a tire size penalty as well.