303 is what I use long before any others. Many don't even feature the UV protection, basically just a cleaner with some sheen, often silicon. While not aimed at painted parts I don't think it would hurt either, help clean, and add a coating that repels dust and future dirt. Like anything, you'd need to degrease and scrub if you planned on repainting the part in the future, plus more likely to have even more harmful coatings on it over the years.
