This thread made me check the test depth for the VIIc listed on wikipedia (not the most reliable I know, but a fair starting point) vs in-game.
I won't post the actual depth my sub popped as I'm sure many of you won't want to know, but I was quite disappointed to find out it was lower in-game... maybe 15-20 metres below the wiki listed
test depth, not the listed
crush depth. Hull damage started a good 40 metres above the listed crush depth.
So if you do mod test & crush depths properly, I for one will be waiting to install it! Though I do like the gradual 'hull damage!'... 'flooding'... 'heavy flooding'... *pop* when the sub is undamaged, but if hull damage is already fairly heavy when you dive, an insta-pop below a certain depth would be fine.