mixing and matching brands

[StSomewhere]

it is actually against HSE regulations to sell or service regs that combine different brand first and second stages (not the gauges!). So, please, please, please, stop recommending it ... it is illegal and could harm or even kill a fellow diver.

OMG, you have got to be kidding me! What do a bunch of bureaucrats know? And you trust them to decide for you? :06:

All the CE does is say the regs have been tested as a unit and the WOB figures meet some horrendously inferior standard, say a WOB of 3.0 or lower at a given depth and flow rate. As a point of reference, the new Apeks XTX200 has a WOB number of something like 0.41. I wouldn't own something on the order of 3.0 on a bet, and yet your HSE says that's OK? Now ask who exactly is going to kill a fellow diver if you have a panicky OOA diver sucking off the same crappy (but CE approved!) first stage as his buddy at depth?