Best accessories/mods for my Convoy S21E ?

I'm simply in awe from the price/performance ratio. Truly a gem in my collection. Best part is that it lasts almost 200 hours in lowest mode, which I use most of the time. Enough for midnight bathroom trips or a sneak to kitchen.

Now I want to do some mods. I know of crenulated bezel and magnet, can i add a tailcap for instant turbo ? Anything else ?

Detailed test results and review is in comment below.