I have heard this so many times, there is a good amount of info about turbo motor life at gary donovans web site
www.thedodgegarage.com
Anyway, Chrysler can't afford for the motor not to last through it's 7-70 warranty, and all the performance magazines that have looked inside, say it is one tough motor. So as someone with 3 other 80's chrysler turbo products, don't worry so much, use mobil 1 and change it regularly, and give the turbo idle time, and I think you'll find the car will last a long time. Worry more if you have an A604 (now called 41TE) autostick trans,, but thats another story.
As for turbo life, my 88 daytona shelby z had a motor rebuild at over 150,000 miles, the turbo was tighter than anything else was, and that car had been really abused before I got a hold of it.