Welcome Chris!!
1989 Spirit Turbos rock!!
Along with what Cordola posted:
Up grading to a stock T-II Garrett or MP Super 60 Turbo is a great "bolt on".
Our are an oddball turbo/exhaust manifold bolt pattern that limit options.
The manifold could be re drilled for conventional Turbos if desired.
Bolt on Turbo oil/water lines are available for the Garrett and MP Super 60.
Beware of Super 60 Turbos that aren't MP as they don't bolt on.
Many Turbos don't have the water cooling provisions that ours have.
FWD Performance and Turbos Unleashed are trusted vendors.
Both can supply Turbos and other good stuff .
Not at ebay prices but also not ebay quality and they will fit.
A free flowing exhaust on a 2.5/Mitsu combo can hit stock over boost easily.
Something to keep in mind if you run into this issue.
Best of luck!
Thanks
Randy
PS: Great site if you haven't seen it yet:
http://www.gusmahon.org/