LS/Vtec or Turbo LS?

Which has the better hp/cost ratio? My friend has an LS and wants to go either one way or the other, but isn't the richest person... I know the possibilities with turbos are near endless, but that sounds really expensive relative to slapping a vtec head/ecu on what he's got. I know any B-series will fit, but what's a good head for the ls/vtec conversion?