Giving everything a quick degrease and a clean doesn't mean having to show up with a "granny car". I'll use my old KE35 as an example. In addition to the mentioned twin carbs and extractors, it was also lowered, had as much rubber stuffed under the guards as would legally fit, mags and a custom paint job - hardly granny spec.
Also as i tried to keep it looking neat and clean, I never had a problem with police roadside inspections. They generally will not look that close if it appears looked after. The same goes for motorsport scruitineers. A quick spray of carby clean just before scruitineering saved me a lot of hassles :cool: