well either way, i'm fairly confident that you'll need to fabricate some custom mounts, or try and find someone that makes a swap kit. for it. you'll have to make yourself a custom driveshaft that mounts up from the rb25det transmission. if you're going to swap an rb26dett, you'll need to use an rb25det transmission.
another swap you could think of doing is a vh45de swap... it's a nissan v8 used in the q45 luxury car, and there is a swap kit done up for it (or in the making i'm not sure) done by speedline. (
http://speedlinegroup.com/)