I don't think these relatively lightweight A Bodies will work you very hard in terms of steering effort, but the ratio (I think it's 29:1) on the manual boxes sure takes it out of the autocross competition.
The essence of adding a turbo to one of these little cars is one of infinite variety in the build. That is, you're only limited to what your imagination can conceive. I would bet that there is room for both power steering AND an A-C compressor on a /6 turbo'd A Body car if it's a mild build that doesn't require an intercooler or a header. Those are two items that can take up a whole lot of room, but may not be necessary unless you want 300 HP.
It might necessary to utilize one of those aftermarket A-C systems with a more compact compressor, but I'd imagine that it can be done. Lotsa room under the hood of a /6 A Body.
Good luck!:cheers: