Nope they'll hyper flash the standard flasher unit is a thermal one needs the 42w power draw to flash correct speed ( hence when one blows it flashes fast) when you fit led they have low draw so flasher unit thinks bulbs blown .
Only couple of solution deal with the flasher unit or fit load resistors to each of the main indicators (not side repeater)
Dont buy a 3 pin led electronic flasher unit theg dont fit z3 has 7 if memory serves this was why i decided to fit resistors at the bulbs (creates the load where it originally was ) then I wasn't going to mess up the electrics.
What sort of leds have you bought
@Nodzed