there is a guy in SA you can buy mounts off for $120 which allow a direct bolt in for a 1JZ onto an S13 X member, Ceffy X members are worth a shiteload more cash than S13 ones, so you can probably get your $120 back on that with no worries
once that is done its a bit of wiring and some plumbing (as you would need with any conversion) and youre set...the only real expensive bits I can see are $1500 for an R154 (but you pay nearly that for an RB25 box which is weaker anyway)
I was seriously going to do this with a GT3037S Pro into my laurel if i didnt sell it.