As for the use and cleaning of both, I think I would be fine, instead for the stems almost always use the originals, having to be as stealth as possible, with the original stems which steam is fresher?
They are probably equally stealth, despite their differences all around, their on demand nature and their form factors make them both work well as out and about portables.
The TM stock stem with cooling unit does offer more cooling, however I would say the vapor is less fresh as more of it goes through more steel? The FW cooling stem works well and is all glass, the vapor may not be cooled as much, but it is fresher being all glass?
TM has the extra long stem, that is similarly all glass with spike indents for cooling, but since it is much larger it is more of a home piece... Meanwhile FW with WPA is fantastic with j hooks too, and I actually almost exclusively use my TM at home now through jayhooks with WPA as well... That will give you the best vapor quality overall!
Is it possible to insert 2 cooling units in the same stem as the TM if desired?
The long stem can fit two cooling units, but that shouldn't really be necessary, you could also open up the cooling unit and add glass or ruby beads for more cooling that is perhaps purer? There are a lot of options and probably more to come in the future! Just using one cooling unit with the short stem is pretty good out and about though in my experience
In case you decide to order a TM is it possible that there is only the .com site and not the .eu?
Yeah there was some confusion about that in the past, I'm not sure what the result was, I suggest looking into it, or use the .com if unsure?
I just got my second TM this week, shipping time is pretty fast right now, you should have it in your hands in under 2 weeks... FW7 is actually a little tough to get right now, like Lamart Tetra...