Dont think the arguement has ever been about power loss while installing a BOV.
When accelerating power will always be the same as video explains as both valves will be shut. What problem is on 1.8Ts is changing gear and metered air.
I have one fitted and the arguement against, which im pretty sure is correct, is that when you change gear, BOV vents to atmosphere which means less air in system, so over fueling happens for a short time after gear changes.
For those with new engines

(mines AGU) you have 2 sensors, MAF and MAP and these must have similar air readings or will throw the ECU into limp mode?
I have tried,
007p cheap copy - spring was too weak, didnt get new one.
Baileys DV20 - doesnt work,
needs to be twin piston.
Baileys DV26 - works OK on my AGU IMO. lots will disagree.
Forge 007p - works great.
The dual piston valve works, i think, by only letting air vent to atmosphere under load, where as the DV20 or single piston ones vent to atmosphere as soon as throttle is released, and from
my experience with AGU, this causes car to stall and run really rough.
Plenty will say what im doing is wrong, and messing my car up i expect, but this is all from
my experience, on
my car.
Im happy with how everything runs at the min, but i will be putting 007p back on for when i get to stage 2 as 1) R-Tech dont like them

and 2) bored of the woosh

Let the grilling commence
