Its easily achievable on the RS6's to hit crazy numbers both HP and Torque, thing is they are bullit proof and can take it without much effort - Engine and gearbox. People like MRC tuning know what the limits are and will remap accordingly to your current mods so nothing is over stressed.
RS246 is one forum that i've never really set eyes on, Ive been on there once and hated the whole layout of it so didn't bother. But I agree, forums like this and others such as the GTROC and MKIVsupra seem to be more laid back when it comes to modding their cars and not so judgemental, that's why I can't keep away from here even though the Z got sold years ago! I think most are up their own arse alot of the time and don't even realise it but anyway......
I reckon give it a year or two and I may be back in a Z or similar, GTR possibly as I can't see the logic in spending 4 figure sums everytime my car needs a service and some work doing to it!