This paper is concerned with correct specification and validation of quality attribute requirements (QAR's) that cross-cut through a diverse set of complex system functions. These requirements act as modifiers of the systems level functional requirements thereby having substantial influence on the eventual architectural selection. Because system designers traditionally address these requirements one quality attribute at a time, the process frequently results in QAR's that contain subtle conflicting behaviors. This paper presents an approach to QAR-induced behavior validation and conflict detection via execution-based model checking early in the software development process.