There have been dynos done that prove that BIG VTEC makes more power than the small prmaries, have seen as little as 80whp to 200whp difference on a full race car. The small primaries do not have the lift and duration to get all the air in the engine, heres one story that proves the BIG cam makes a difference. Also some Drag Racers lock the BIG cam on since having a smooth idle is not an issue, check this out

http://www.hondata.com/dynogsrturborocky.html

I seriously dont know where you are getting your misinformation. LS motors make good power due to the displacement and the cams are agressive enough for turbo and would make more power than a B16A if the VTEC was turned off since the primaries are MILD!