Actually the whole front of the gearbox is different. These don't have the separate bellhousing. Its incorporated into the gearbox casing. So trying to find the bits to do a swap would be challenging.
I'm also not sure how similar these are to the S15 200SX boxes. The shgifter arrangement is totally different and I think the shift pattern is different too.
Might be worth the $3K if it does have the TRD close ratio set in it though. I would doubt it if its just come via an importer though.