Oh, wait... my mistake. I thought you were referring to an accessory, like a 5-in-1 reflector, or somethin'. No, I see what you meant, now. I get it.
Yeah, the reflector - the one you're talking about that goes behind the actual tube, and stuff - that changes the quality of light. White is generally softer, silver produces a 'crisper' light with a little more contrast, a little more 'pop'.
On my DIY, I painted the inside of the Bundt pan the purest, whitest, damned white I could find. The outside was the flattest, deepest black I could find. Both in spray can. Then I baked the pan in a production oven for a few hours at a low temp. I went with white because I knew I wasn't going to get it shiny silver on the inside and even if I did, it might be uneven, which would have left hot spots.