My approach is hot side for 4 reasons.
> It is meant to protect the compressor it is closer to the compressor.
> When it dumps it dumps hotter air so helps intercooler efficiency.
> With auto gear change cool side long route pipes remain pressureised so lessons lag.
> The blue people are getting tough on mods and want no fuel venting, cool side has possibility (?) of sucking the fuel vapour coming in the inlet from the pcv while hot side is pressurised all the way back to the inlet manifold and is freshly filtered air that is venting.
as has been mentioned already, no major performance differences. just maybe (in my experience) when you place it on the hot-side, you get more 'whoosh' whilst placing it on the cold side gives you more chatter (squirrels). i had my setup just like you on the cold side but loved the squirrels so much that i ditched the DV altogether. now i have squirrel chatter all day everyday.. & i don't mind it one bit since i'm not trying to save 0.375 seconds in between shifts anyway..
i had to put mine on the hot side, no takeoff on the t/b i/c pipe, and yes its louder for some reason, . I do miss seeing it in the engine bay tho. its now under my td04 im gonna loosen the screw to get a more gentle whoosshh, right now it seems a little harsh PTTSHHHHHHH!!