The scope of this document is not intended to endorse or discourage modification of original equipment chassis or settings. This paper provides guidelines describing some of the issues that must be considered when undertaking any form of vehicle suspension modification. While every effort has been made to address most types of suspension modification, this document is qualitative and is not all-inclusive. This document is not intended to endorse, regulate, or limit the degree of modification, or to be interpreted by regulatory or enforcement groups as establishing such limits. Sound engineering principles must be applied in the development of any and all proposed alterations. It is recommended that all aspects of modification must be supported through analysis, and should be verified with actual vehicle and/or laboratory testing.