I got my S2+ Desert (8*7135 Biscotti U6 3A Tint) today - I am happy that I bought it to make another triple 219C light out of it.
The hotspot looks pretty ugly - white on the outside and yellowish on the inside - meh.
But that color and that finishing - just really nice. I like the matte finish of my M2 really much as well.
I have to agree with the color and the finish of the light.
I had the chance to use lots of lights, but the matte finish of the Convoys is one of its kind.
I updated the OP in order to add some outdoor beamshots I captured.
What’s the difference between biscotti driver ans stock driver of the S2+ sand?
How to get the S2+ sand with biscotti driver?
Who else did replace the smooth reflector with the OP one?
And anyone combined colors of external parts, like sand in the meddle, black in the front and back?
a) The differences are that the “stock” driver is a 3/5 mode in which you can have 3 or 5 modes (L>M>H or L>M>H>Strobe>SOS) and biscotti has 12 different options of modes.
b) Biscotti can be obtained if you contact Simon of Convoy Flashlight Store in AliExpress!
c) OP or SMO can be replaced with no problem in these flashlights. XPL-HI + SMO gives more throw, while XPL-HI + OP gives less throw and a slightly larger hotspot. However, using XPL-HI Leds you will always have a more throwy beam.
d) Tubes of different colours normally match among the same model of flashlight (Convoy S2+, either it is black, desert tan/sand, grey, blue, red,…)
I modded my desert tan S2+ with a black 18350 tube.
I put an orange peel reflector on my sand S2+. I like it because of the slightly larger and more diffused hot spot. I’m more a fan of floody lights and this simple mod gave me more of what I like in this light.
Get a Gas torch. strip the centre section of any O,Rings. then, holding with a pr of long nose pliers. Slowly pass the flame through the tube. rotating as you go. Be careful there are different shades of brown depending on length (time) of heat application.
But you can come up with some nice shadings. I’ve done several now.
Specially my S41 with red 18650 centre tube. Black tail, shading through to Copper head with stainless collar at LED end.
Also. For the locking collar job. (I’m a retired Diesel Tech) I use a coupla prs of Stainless needle nose pliers, small and tiny.
They need Popeye’s arms to bend the tips of them (chuckle)
The mild steel cheap ones bent tips easy.
Your S41 sounds quite special.
Could you upload any picture for us 
?