Actually it looks like a swap is as cheap if not cheaper then a turbo kit, let's compare some prices you could find on the net....
Unstable-Hybrids Will install a SR20DET for $4050.
A FMAX Stage 1 kit all buy itself not installed costs $3999 at
Rollhard.com or the NSport which costs $3300 not installed. So the price for over the counter turbo kits looks more then having a SR installed, of course they give you more power then having a stock SR put in, so it's a trade off.