I noticed two rotary engines, one on them, the intake manifold are smaller and the other you notice on the intake manifolds that there is a little split between the two and look bigger? can someone tell me whats the difference?

 

RE and REW?

 

i believe one of them is the 13b cosmo. Not 100% sure though

all of the us FD's had the one with the intake manifold that has the split. the other one should also have 13B printed on the UIM

 

There are many versions of the 13B that are diffrent. You have the S4 NA, S4 Turbo, S5 NA, S5 turbo, 13b RE, and the 13b REW. They all are diffrent in there own little way.

 

if you had the 13b-re and the 13b-rew which one would you bring for a rebuild and streetport or there is no difference