For my money, the 9Z is a bit of overkill. I don't find the extra battery life or brightness(?) to be a factor in my civilian role. However, the extra size is just enough to keep me from carrying it as often as the 6Z.
The 3P also makes a great stocking stuffer. While it doesn't qualify as a "tactical" or "combat" light, it's cheap enough to leave permanently on the bedside table.
Turning to filters and diffusers, it's already been pointed out that red preserves night vision, while blue is useful for spotting blood. I've used the blue in airplane cockpits, as much of our aeronautical charts are in red and red light obscures it. If you go with a filter, I'd suggest the red. I own one for use at the campsite.
Given the tactical advantage of that bright white light, I side with Walt's comments elsewhere and prefer to keep the attachments in the gear bag. As I don't picture *my* tactical scenarios requiring a prolonged or active search in unfamiliar surroundings; more likely a sit and wait, light 'em up, shoot 'em up.
I'd prefer an acutely directed, bright, white light for this scenario. The wide beam diffuser may be an option and I intend to order one of these to test it.
Hope this helps.