Well. it looks right...and pretty, too.
It could be that this car is the first tactory (right?) turbo'd engine with a groove on the TB.
I think that means we especially want to see a success here.
By my understanding of turbos, they use exhaust gas flow to push extra air into an engine above a certain RPM. The groove on the TB would work up to the point of the turbo kicking in - so, to get the fuel efficiency benefits of the groove, you need to keep your foot OUT of the turbo range more often than not. HOWEVER - what may not have been attempted is placing a groove at the outlet of the turbo/intercooler into the manifold.
how many inches of boost does the turbo create? pressurized air hitting a groove should make for a fairly significant vortex waveform in the manifold...
IF I'm right, you could get the benefits throughout the rev range of the car
ok, here's where I'd need clarification - does the turbo dump it's output upstream of the TB? I was suggesting a 2nd groove at the place the boost air enters the manifold
the groove should help you get up into boost territory faster the way it is now, but once you hit that point where it spins up and kicks in, it would be all air, fuel and spark.