I don't know the origin of the Zuks axles but the Sportage are from Mazda. Alot of makes use the same loocking hubs but that does not mean the inside of the axle are the same. I crossed referanced part numbers and the front is the same as the Miata with the exception of gear ratio and the rear is the same as the RX7 with the exception of gear ratio. I will be trying a Miata LS as soon as my boys freind is done with it. He is building a 302 for it and will use a 8.8 rear IRS. If a Zuk locker would fit that would be great but it would take someone with both vehicles to try it, if it does'nt fit the Sportage put in in your Zuk.
Dennis

95 Sportage, gone but not forgotten.
98 Jeep TJ, 4" Zone springs with RC Long arms, Ford 8.8", 4.56 gears & Detroit locker rear, D30, 4.56 & Detroit Trutrack front.