I have to chime in on this one...

IF you adjust your BOV so that it does not LEAK under idle then your idle will be the same as if you recirc. all air being metered is being cunsumed.

now...as for the running rich after shifts bit...yes it happens and yes it can cause drivability issues (i have fouled plugs from lots of low speed and part throttle driving). but this can be fixed by a S-AFC.

BTW...Greddy R can also be recirced...it has the threaded outlet as well.

Scott