Post #33 shows how Kramer went about getting a 7135 driver in there but its worth reading the whole thread, there’s plenty of info. Not sure what you mean about the reflector as its smooth anyway, you can sputter it to smooth out the beam but I’m unaware or replacement reflectors available.
It may also be worthwhile having a read through this thread for additional information, I’ve not organized it yet, but its supposed to be a reference guide for modding.