almost everybody on this forum is going to tell you this:
ALWAYS GET A FRONT CLIP WHEN DOING A SWAP!!!!!!!!!!!!!!!!!
you will have EVERYTHING and you won't have to go look for things that costs a LOT and a LOT of time.. ex.) ignitor chip is 350$ and are sometimes missing on motorsets. another reason why you should get a front clip is you might get some freebies

i know of ppl that got hks triple-plate clutches in their cars..t28bb turbos in their s13 sr20det clips..brembo brakes..etc, you get the point.. GET A FRONT CLIP
i think the seats will fit but you might need custom seat brackets..