wow, there is alot of people in here saying alot of hear say about rotarys , unless you own one you prolly don't know what you are talking about,
I think it would be a sweet swap.
go for it.
and there is ALOT of people in the states who can port a rotary,
I am one of them,
I ported my ols s4 n/a motor, and made 160whp w/ only intake exhaust and a small street port,
if you know what you are doing you can easily/safely get a 13b n/a to around the 250whp range.
but if you are doing a full custom swap I say find a 13bt motor!