Little British Car Company sells some upgrades with more wattage and light, but it gets a little pricey to order multiples, you can get LED lights as well, but a little trickier to get the right ones, many are somewhat directional, like a flashlight, and you want one that diffuses light in all directions or a multiple LED light that shoots the light in multiple directions. If you want to venture out beyond the usual British car suppliers you are looking for a 12 volt bulb with E10 screw base. Google that or search on E-bay, all sorts of things will come up.