just make sure you swap over all the parts to the b13 sensors and stuff.
also, the ps pump is different, so you'd have to use b13 ps pump, the water lines are different, as is the coolant temperature switch/thermister switch. So again, just unbolt the b15 one, bolt in the b13, and you're on your way.
oh and the b13 oil filter bracket, ac compressor bracket and I believe the motor mount brackets are different as well. No big deal, all bolt ons, the block itself is good to go.
And since you are swapping the ps pump out, could you hook me up with a part? I'll trade you it for all the knowledge you can grab from me since I'm doing this swap right now
BTW, make SURE you measure with a digital caliper the head bolt lenghts, buy a head gasket, and make sure the bolts are within spec (6.288" i believe is spec, but check the fsm to make sure. length is measured from bottom of bolt to bottom of head)
Head bolts are 11mm Allen key (get a socket with a longass head)
Welcome to the forum, and make sure you turn your PM box on if you have any other questions you can pm me and i'll help you out.