the FS ZE engine from japan is worthless without the Jspec ECU from that car. the wiring involved is completely incompatible, making the swap completely cost inefficient and not at all worth the effort.
if you are looking to go the naturally aspirated route, you can buy higher compression pistons, cams and cam gears, pulleys and other such goodies. in the end, you'll get more ponies per penny with a turbo.