Collection: Additives

Protect your engine and maximize its performance with our high-quality fuel, oil, and marine additives. Whether you are winterizing your boat, treating your RV’s fuel system, or boosting your daily driver’s horsepower, DIY Customs has the right formula for the job at unbeatable prices. If you don't see your preferred brand or specific additive, hit the live chat or call 412-882-8346—we special order and drop-ship directly to you!