There is nothing wrong with these cars, I drove one for 5 years as a daily driver with out any major issues. If you want more speed then convert it. It is a lot easier than you think. I have converted many 84-85 into 86-87 setup using the 84-85 long block. We even had an 85 short block, stock cam go 10.60's @126mph and few others in the low 11's. If you want to do that just slowly collect 86-87 parts you need off this board, sometimes people sell them so cheep . If you get the basics parts, then things like turbo, IC and thing you can always buy after market ones.
These cars(84-85) are fast and fun to drive as it is and if don’t care about beating everybody on the street you will be happy with it.
Just my $.02
Prasad