Maybe sometimes for better fitment.
The need for additional modifications for diffuser installation can vary depending on the specific product and the vehicle it is being installed on. While some diffusers may offer a straightforward installation process, others may require minor modifications to ensure proper fitment. These modifications could involve trimming, adjusting mounting points, or making slight alterations to the vehicle's bumper. It's advisable to carefully read the product description and consult with KOCF's customer support if needed to determine if any additional modifications are necessary for the specific diffuser you are interested in.