Assembly simulation plays a pivotal role in predicting and optimizing the distortion of an assembly, particularly in the automotive industry where precision and efficiency are paramount. In BIW parts assembly, factors such as clamping, mechanical & thermal joining, and loading direction are important. These factors affect the quality of the final assembly. Predicting and optimizing these parameters in the early design stage can help reduce development time, cost and improve the quality of the final product. Currently, LS-DYNA is used for closures like doors, hoods, and fenders. However, the pre-processing, computation and post-processing time is significantly high in LS-DYNA making it challenging to use for the Entire BIW. Employing a comprehensive approach, authors assess the distortion results, preprocessing, calculation, and post-processing time of both simulation techniques. Notably, the study reveals that AutoForm offers over 50%-time savings across all stages compared to LS-DYNA without compromising result accuracy. Moreover, AutoForm demonstrates reduced resource utilization and calculation costs, making it a compelling choice for BIW subassembly simulations. By leveraging advanced simulation tools like AutoForm, manufacturers can expedite the design process while maintaining stringent quality standards, thus gaining a competitive edge in the market.