Advanced Driver Assistance Systems (ADAS) are becoming common on passenger cars and pickup trucks. Accordingly, the manufacturers and installers of aftermarket equipment for these vehicles have an interest in confirming the functionality of ADAS when their equipment is put in place. However, there is very little publicly available information on the effect of aftermarket components on original equipment ADAS. To address this deficiency, a research program was undertaken in which a 2022 Chevrolet Silverado 1500 light truck was tested in four different hardware configurations, including stock as well as three modified conditions. Aftermarket modifications to the vehicle consisted of increased tire diameters, a level kit, and two different lift kits. A series of physical tests were carried out to evaluate the ADAS performance of the vehicle with modifications. Tests were designed to investigate differences in driver alerts including lane departure warnings, forward collision warnings, blind spot detections, and rear cross traffic alerts. These tests were also developed to assess the variation in vehicle responses when driver assistance technologies intervened. Intervention scenarios examined include lane keeping support, crash imminent braking, and traffic jam assistance. In general, results from the tests did not indicate significant ADAS performance differences when the vehicle was subject to modifications. Nevertheless, some tests showed a greater range in alert distances in certain modified configurations.