This is direct replacement for the Airfix part. At first glance you might question why a replacement is needed as the kit part is actually very nice. Upon closer examination you’ll see that Aires has spared the trouble of drilling out the exhaust tips to represent the open ends of the pipes. It’s worth the price of admission if you what to avoid that tedious task. The parts are easy to get off the casting block and a perfect match for the mounting holes on the base kit. Aires also makes another set with fishtail ends (set # QB 72 483) reviewed elsewhere in this site that don’t come in the Airfix kit. Thanks to Aires for improving an already great kit.