I recommend using a LED bulb then. They are much brighter then standard halogen bulbs, you will just need to find which design works best in that housing. This is a great idea that updates the looks of the 996, it is just a trial and error type process as you have learned. As you can see in my avatar, I did this same thing to my E46 M3, along with upgraded crystals for the projectors, and new lenses to cover the housings. I also painted my chrome bezels high gloss black. I love the look now, as it looks more modern and menacing at the same time.