Strobes are so-so. They've gotten to the point that strobes are now a special order with some fire apparatus, as they'll only offer halogen or LED as standard. If you run them at higher wattage, they might be okay, but then you're gonna burn 'em out quicker depending on how often their used. Now, 700 series strobes on a fender would look better than the 500 series, as they'd be bigger, giving a bigger footprint from a distance. Those have been used on a ton of SUVs and ambos.
Just cuz you got something laying around doesn't mean it needs to be used or it's the best application.