to the OP


as stated you need new knuckles - why? Because the 2 mounting holes for the caliper behind are slightly further apart for the 262 and also 282mm brake setups.

you can use the knuckle , disc and calipers off

eg6 , ek4 , 99+ek1 , em1 , dc2 and dc4.
all the above came with the same knuckle and same 262mm setup.
just remember to get front brake pads to suit the CALIPER (for example ek4 caliper needs ek4 pads) - the pads are slightly different model to model.