a whistle vs. air going inside a tube? i bet you won't be able to deliniate between the two of those sounds when riding in the car. actually, regular non bb turbos give out a whistle when spooling. i really don't know how ball bearing turbos sound, but i'll bet they sound exactly the same. its not the bearing/journal spinning that makes the sound. its the highly pressurized air passing through the turbo and piping that makes the whistle.
and you are correct, stock vr4's do NOT have bb turbos.
honestly, i don't know of any vr4s running bb turbos. they're just way too expensive and not that much better than regular turbos to merit buying the bb. basically, all the ball bearing does is prolong the life of the turbo. and even if a regular turbo gets old/needs rebuilding, it is VERY simple to do yourself; the rebuild kits are only $150-$200. here is a write-up with pics on a turbo rebuild
http://www.vfaq.com/mods/Turbo-rebuild.html