you are about right.
sr20det = 205 hpish
ka24e = 140 hpish (sohc)
ka24de = 150 hpish(dohc)
i think piecing a turbo kit would be cheaper than an entire sr20det swap + mods though. and tearing apart an engine isn't that hard, it's putting it back together ;] it's all a matter of what they want though.