any tips about dealing with cops in Poland? 

I know that in Germany the "right to remain silent" is quite theoretical—if you refuse to give your ID or answer about ID-type information (name, address etc.) you can be detained up to 48 hours (probably details vary by state) and give them cause to go through your stuff, search your house and whatnot, plus if you're a witness you're obliged to talk anyway unless it would incriminate you or a close relative (meaning that refusal to snitch qualifies you as a suspect, so you're treated like the suspects, e.g. with the detention thing. cops are allowed to force-unlock your cellphone by fingerprint or face scan but not (theoretically) force you to say the password or unlock it yourself (though they pretend they are). German cops can be filmed or photographed, but they pretend it's a crime and harass you about it. German cops are not allowed to use torture methods but they do, routinely, did to me every fucking time. and cops will try really hard to get you to sign to scammy documents (where the fine print makes you authorise searches, consent to their behaviour, admit to guilt etc.), but it's safe to always refuse to sign; there's no situation where bad things can be done to you as punishment for not signing something.

if detained in Poland can you just go, "no comment" to every question until they let you go? are you expected to bribe like in Brazil? any particular traps when stonewalling Polish police