Mainly Pass by Noise (PBN), exhaust backpressure, durability & reliability; exhaust brake performance, aesthetics (if visible from outside chassis), cost, weight and safety are the key performance evaluation criteria of any Automotive Exhaust System. Introduction of different Exhaust Aftertreatment System/Devices (EATS) call for additional emissions evaluation for Exhaust System from EU4 (or BS-IV) onwards. In Engineering Function (R&D), key focus is given on above performance parameters of any design and development or New Product Introduction (NPI) process. This paper covers a critical problem faced by downstream function of NPI process and its resolution through Design of Experiments (DoE) and Pugh Matrix Analysis based on QDCFSS (Quality, Design, Cost, Feature, Safety and Sustainability). Design for Assembly (DFA) is critical event specially at the pre-launch production phase. It has the dependency with design, parts (piece to piece variations- like dimension, material property), method shop floor facilities/resources (workstation - tools/machines), method/practices (variations - plant to plant / location to location) and workforces (training and physical states - like height). In subject case, torque loosening/variation and difficulty in assembly has been reported from different plants globally for mounting of exhaust tail pipe of EU6 heavy Trucks. In this context, multi-objective optimization is done vide DoE and Pugh Matrix evaluation to resolve production/manufacturing blocker problem of EU6 global trucks. Also, Quality Tools are used to do the Root Cause Analysis (RCA), find out Interim Corrective Action (ICA) and come up with different inputs for DoE. The primary objective of this research is to investigate and optimize among the factors and finalize the strategy of tail pipe mounting scheme which consists of tail pipe (GD&T and material), mounting clamp, torquing and orientation preference. In material selection, Sustainability which is focused based on SOC (substance of concern), CO2 reduction and R-Cycle framework, is equally important in decision making. This work indicates that DoE technique with QDCFSS assessment is very much effective to optimize multiple factors and resolve the problem from R&D function to ensure business continuity. Keywords: Exhaust, Tail Pipe Mounting, clamping force, Tightening torque, Optimization, Design for Assembly, Design of Experiments, Darcy-Weisbach equation, Sustainability, Pugh Matrix