Hey how's it goin?
Well probably the easiest and cheapest(but also the least powerfull)of any conversion in that car, would be putting in a 5k corolla engine( from a ke70 i think?)
Then you could consider any of the 4ag series engines from the 86kw version to the supercharged 4agze version,
depending on how much u want to spend.
Will u be doing the work on the car or will you be getting someone to fit it for u?
At the moment im considering a carby turbo conversion on the 3k in my ke30 so thats also an option for you to consider.
hope this helps anyway.
vr4gsr.