Re: Audi 4000 Quattro 2.3 130hp NA or 10vTurbo swap (NW4KQ driver)
I voted 10valve turbo but also have a NA ~130hp engine and enjoy each for different reasons.
The turbo is awesome on the highway, offers massive torque, pulls like mad into triple-digets, was a lot of fun to do, and is easily upgradable. I've got the K26 so there is some lag, but it isn't bad, especially after installing a bypass valve.
The NA car has more throttle response, especially below 2000 rpms, which is good for starting on hills and stuff. It's my daily driver / commuter car for that reason. The engine does loose oomph around 4500rpms though. It was easier to do swap and somewhat cheaper, but doesn't offer much for increased performance. I may swap the CISE-III ignition into it at some point as I think the knock sensor and different timing maps should offer more drivability.
If you want to drive down to south Seattle / Des-Moines, you can try them both and see what each offers.