the full rebuild kit contains new housings, the rotors themselves can be had cheaper from another engine if you want, the oil metering pump is not that expensive either, the iron housings are usually good and even if not then you can get a new or surplus one. The beauty of the mazda RX8 was that it handled very neutral because more weight was actually in the centre of the car rather than on the front axle.
The rebuild kit you are mentioning is called the "sealing kit" which is usually bought when the engine has been overheated, its the equivalent of "headgasket" job on a piston engine.
If you "think" that a toyo JZ swap is a good idea just because your "nukkar" ka mechanic understands how it works then it would cheaper to set the car on fire. Swapping an engine is not just "ye engine iss mein thok do" aur 'ye taar iss se jordo"
and there are tons and tons of sorry JZ, UZ swaps into RXs in the world which became scrap due to becoming basket cases.
and you mentioning that all money going down the drain if the engine dies again... lets say your windshield gets broken, would you drive with it broken because the next one will just break again?