I can only use deductive reasoning to help you out... since I don't plan on buying them.
I can say that there are users on this board that have stacked GenMar and Heli bar risers together for a total height of 1 3/4" rise and said the cables were JUST long enough. Armed with this information I would say that at the VERY least you will need which ever set you are looking for - 1 3/4" longer cables.
However if it were me?, I would buy the X distance longer cable. So 4" risers = stock + 4" longer lines. But working in the world of computer and networking, I would rather my fiber optic cable be 1" to long then 1/2" to short... Cause then you have to break out the cable stretchers... you know what a pain in the ass they can be ;-)
BTW, Coremoto has a sale going on right now for a full set of cables (brakes, front and rear for $139) CoreMoto ZX14r 2012 Cables
I have bought some stuff from them before, had no issues, seem pretty quality stuff. I bought the spiked windscreen bolts, bar ends, front axle covers, and spools, all blue base with black spikes. I have pics posted on here somewhere with my windscreen bolts... someone asked to see them.
Anyway good luck and make sure you let us know how you like your risers when/if you get them and what you did for the break lines... I always enjoy a good product review.
2012 ZX14r / 2002 VTX 1800c
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Intelligence Has a Price...
I Sure Wish Everyone Could Afford It.
-ME