Single is out of the question, to much lag.
Most singles will have a lot more lag. People often mix up spool and lag. Spool is rotordynamically driven, meaning
where in the RPM band you make power. Lag is responsiveness,
when you make power, or
"time-to-torque". Spool and lag are certainly in bed with one another, but are not the same thing. A dyno plot will show you spool, not lag. You guys know this, just not all of you have put 2 and 2 together. Think of the big supra drag cars you see staging at the line. How long do they spend spooling up the turbo? Now imagine how that 1/4 mile time would change if they had to start the race at a steady-state 5 mph. Great dyno plots though, and perfect for their application, but not useful for real-world driving (most of the time).
If you want a responsive vehicle, you want turbos that spool early in the RPM band (important!) and have extreme responsiveness (important!!). This translates into a very high degree of "driveability", and for most people it means more fun. Other platforms (especially NA) spend a lot of time and energy pursuing that responsiveness. There is a reason for this.
IMO large turbo small displacement engines are boring to drive anywhere but a track or flogging it 10/10. Turbo design and motor tech has certainly made it a lot better than it was say, 10 years ago, but on anything but a race car a laggy turbo mostly just adds angst when trying to perform real-life maneuvers, like pulling out in front of someone in traffic and needing a reasonable amount of power
right now. Most of you have experienced this. Pedal on the floor.... wait.... wait.... car getting closer in your mirror..... Oh, hey, there's some power, thanks for showing up! You can reduce a lot of this frustration with predictive driving habits -which is always a good idea- but a low-lag turbo system wins all day long IMO.
Now on a dedicated 1/4 or 1/2 mile race car, who cares, all we want to do is move the most air possible, she could take as long as she wants to spool up, once it's go time it'll stay spooled for the whole race. This would be why we have large turbos on the Stage 3 kit on the shop race car.
On the V1 GC series the lites had significantly better spool than the full GC's. The GC V2.0's close the gap considerably. So much so, that's what's going on my personal car (still have the old Stage 2+'s on her!). To each their own, of course. I generally talk with customers about power goals, how they actually use the car, what transmission, fuel, etc and help them sort out what's the better fit for them.
Chris