well i have actually seen a few street ported rotaries that are slower than stock ports.... so id mod it till u dont think you can anymore and then buy a ported engine or port another block out yourself and then you can compare the differences yourself.. i have heard from my car club pres. that porting not only looses torque but unless ported right you can loose hp too... therefore thatz why some street ported rx7's u see around town only sound fast.. lol my brother street ported his 91 engine inside his 87 base but i havent seen him get on it seeing that it has only a few miles on it.... ill keep u informed
jack