you could go with either motor. the wiring harnesses are the same. you just have to match up the right computer and thats not hard to get. i have a spare 89 2.5L turbo computer.
actually your best bet is prolly to keep that car stock (ie reliable) and change all the fluids (especially the trans fluid) and get a project car to tinker with.
one of my friends is selling a 88 shadow 2.2L intercooled turbo 5-speed on www.turbo-mopar.com. redpunk101 is his name. the car is in warsaw. very solid body, decent interior, needs some paint and needs a bunch of tinkering. he wants ~1000$ for the car.
im going to be selling a 88 plymouth reliant with a 3.0V6 5-speed conversion as well (soon as I put the interior back in the car and fix a few things) 60k mile motor, fresh full rebuilt trans from Cliff Ramsdell (if you are into TD’s you know who he is) 88 shadow turbo bucket seats, new struts/shocks as of last year, brakes gone over last year as well. 1000$
Brian