AFAIK, Sealantis is the main authorized distributor.
You can try this newer dive shop in PJ - Scuba Warehouse. I was told they have Scubapro products as well. Not sure if they have all the range of products though. Sealantis doesn't carry all of Scubapro products. Was looking for a BCD once and was told they don't have it, even when I wanted to order also they say they don't have it hence they won't do so.

I doubt you'll be able to test the regs underwater though. Unless you have friends who has those regs.

If you can afford it, go for Scubapro.