Just out of interest what set up you using?

Years ago i got a caprisport kit using 283mm cossie discs and mondeo calipers(cos it was easy and cheap)

But cheap turned out the be the problem as once assembled i had approx 6mm of pad overlap(shit design and enginering!!!!)

So being an engineer by trade but not in it anymoreotherwise i could have knocked up all parts required for a better conversion,I done some drawings of parts and had them remade to my spec which ment the caliper carriers had to be machined to fit more onto the disc.
Only done this due to the fact i wanted more pad to disc but as said by tabetha its safe to do so which i've done in the past on the princess 4 pot conversion using std capri vented discs,Then rally design started to do there own grp 1 257mm vented disc which then sorted the problem

Paul