Here you'll find an assortment of information on a variety of topics. Please see my GPL FAQs and GPL's ReadMe file for more details.
If you still need help, try the following resources:
There are many extremely knowledgeable sim racers on the forum at the APEX and on rec.autos.simulators who would be glad to answer your questions about GPL. It's rare that a satisfactory answer to a sim racing question cannot be found on these resources.
If you find a bug in GPL, or have an installation problem, such as an issue with your sound card, please email the Sierra Sports support folks at firstname.lastname@example.org. Unlike email sent to the address listed in the manual, which only returns an automated response, email sent to this address will get read by a human.
Sierra Sports support is also the place to contact if you have a concern about an aspect of GPL's design. Issues which have been raised to me by readers include the fact that there is no way for you to control the speed of the AI drivers, the fact that it is not possible to choose race length independently from damage model and damage recovery options.
Online issues readers have noted frequently include the fact that there is no way in GPL to limit the number of players allowed to join a race, and the fact that GPL's server lacks a command line interface.
Sierra Sports needs to know if you have concerns about these issues.