Have you checked out the SR20VE? I think it's a good option, as you can turbo it just as well as you can the DE, it' makes nice hp NA, and it'll still be fun to drive while you build up your turbo kit.
Fugiot is right about the cost. You won't be able to complete a DET swap for $1500, so you'll be better off just getting a new motor in there for less and building up. You could get a VE motor in there, along with a few bolt on's and get close around 180-190hp NA anyway. It's a pretty potent motor. Check out
www.sr20forum.com and visit the VE section and search in general about it.
If you don't like that option, I would just pick up a JDM low mileage SR20DE. They go for around $500 now I think, and you could save $1000 for your turbo kit down the road. Just my $0.02, but that's what I'd do if I was in your situation.