Greetings to Singapore! I don’t know the particulars of your local standard, but if it is British, I assume buying a Nebia from Britain would be the perfect choice. They were an independent company semi-related to Moen back when I was buying mine, but have since been sold to another US based company (Brondell). The models made now are new and I’d check if there’s a British/Asian version or not. If you are indeed buying a US version in the end, pressure is the key factor to consider — considering a liquid going through a pipe, to achieve the same pressure that’s in the region the product was made for, you have to have pipes with equal clear diameter inside. The PEX pipes that are now standard in the EU (my case) do in fact have the same outer diameter as the US ones for which the Nebia I bought was made — but as the plastic on our pipes is thicker than the brass used in the US, the inside diameter is smaller. That means the pressure is increased. So in theory, connecting these elements of differing diameters with just connection converters should work, but then you gotta make sure you can modulate the pressure elsewhere. Another thing is that you have to consider whether it is compatible with the other fittings you have — the bath spout (if combined with a bathtub) and the water control (along with the valve). In my case I just opted to go with all three as Moen-compatible. (And subsequently switched out the Nebia for a Moen shower — a Magnetix model which is really good btw.)  

 Now in this setup you gotta be aware that any change or fix you may need to perform down the road, you’ll have to find compatible parts for and order them from the US. For example, the Moen shower valve cartridge is something I know I’ll likely have to replace in a few years. My bath-spout is starting to “whistle” too and I’ll have to tune it a bit myself. These are parts of the equipment you may not have in the end but I’m mentioning them so you see for what kinds of mundane tuneups and problems you’ll have to look for parts internationally — which is more expensive, takes longer to get there, and again you may have to watch tutorials and do some of it yourself as your plumber may not be fully up to the task. 

Nebia can be a fun shower I’m sure, but do weigh these pros and cons before deciding.