Wow this sounds familiar...
I have an IHI turbo from a Thunderbird on my 2006 2.0 Duratec with an upgraded compressor wheel. This combo is good for 103mph in the 1/4 max. The power dives off after 5500 RPM, closer to 5300RPM with the stock compressor wheel.
If you have the other version, the T3 then it will flow more but good luck finding one that isn't complete junk. The bolts rust into center section making it darn near impossible to rebuild. I've tried twice.
If you somehow manage to find one that is rebuildable (and rebuild it) then it should be a decent turbo for a stock bottom end. You'll also likely need to run a .06" oil restrictor.
All that being said, I wouldn't do it unless you just really desire on ongoing project that will suck away your time and money.
EDIT: I will be selling my IHI/16T hybrid turbo soon, as I am moving to a GT2871r. If you or anyone else reading this is interested you can PM me or just wait for it to show up for sale in the for sale section.
'04 Mach 1. Built. Turbo. 667whp/631wtq
'06 Focus. Built. Turbo. WMI. (sold)
'03 Mach 1 : 12.61 @ 106.59 (sold)