I'm not sure about in the campaign, sorry if I misread your post. I thought you were talking about the arcade perfect trophy. I know you can turn the weapons off and still get arcade perfect. The best thing you can do is stick at it and practice. Try and learn a new racing line and if you're blowing up a lot you might want to switch ship for a short while if if has low shield or try to be a bit more conservative with your weapons usage, if you don't already try to absorb more to keep high energy.