Main advantage is increased air flow to allow the ports to work, I have some special RICE RACING spec rotors which give earlier port open timing and alter closing, again all designed to work with the inlet manifold.
The turbocharger I have is referred too as 'H' version of the EFR9180, it's got a 1.45AR rear housing on it, I run a V60 Tial waste gate on it.
The full rotating assembly is balanced, clearanced, and lightened to work to 9500rpm reliably and at high output. The engine will have a working range from 4000rpm to 9500rpm, however the parts summed together will have a 'sweet spot' from 5000rpm to 9000rpm @ 2 bar gauge pressure or around 3 bar absolute pressure.
Set up looking for real honest power of about 750bhp to 800bhp @ the engine, that is very quick in transient response above 4000rpm,
below that the engine porting was not designed for really, that was/is more the realm of stock standard Mazda Porting.
To put it into perspective for you (common 9.0:1 CR 13B-REW ancillaries small to medium size single turbo)
Mazda Porting = ~190bhp per bar of pressure
RICE RACING street porting = ~250bhp per bar of pressure
This set up with 7.5:1 CR RR spec rotors and increased timing and Cosmo inlet manifold (note you loose some power per bar of boost due to lower CR! as is normal but you far out gain that loss in increased boost pressure and tollerance to knock) will yield around 260bhp to 270bhp (OR MORE!) per bar of pressure on a 'state of the art' appropriate sized turbocharger
This is due to some trick timing changes allowed by the rotor face contours, all without needing to go to an inferior bridge port inlet
It does get complicated but without giving too much away (all my competitors like reading my posts LOL) its the interaction of all of these parts that makes for an efficient set up, but not only that, what I have engineered is a reliable and durable set up, one that can be used in the real world any where any time and to its full capacity without excuse ............ which is what a real street car is all about.
Lots of things have been in development thus why I have been not on here much, don't fret though all these will be showcased in RICESP and other places that I can let you know about one day
but people like to keep their advantage a bit of a secret for a while LOL......