There are 2 turbo kits out already that should work on the lower-end 4 banger provided some ecu upgrades. One is located in canada and I can't find the link, something like initialspeed.com.

The other is http://www.roadracemotorsports.com/ralliart.htm. The turbo kit on the Ralliart should work on the 4 cyl Eclipse as well because they are the same engine, and since the Eclipse has more room under the hood, so fitment shouldn't be a problem. I would imagine that a little custom ECU work would need to be done though.