How much is your real budget?
Your choices are: buy something cheap
and prolly spend more than you paid for the car on stuff you didn't see. (Money pit)
Spend the cash now and enjoy it from day one and not be frustrated, but if this is your first turbo Buick, you better have it thoroughly inspected and driven by someone that knows these cars.
If they won't let your expert drive it, keep looking.
There are precious few turbo Buick bargains.
There are a lot of overpriced cars.
There are quite a few turbo Buicks here in the Southwest, but even with deep pockets it still took me around 20 years to find the right car.
I did find a LOT of polished dog turds in that time.
Good luck with your quest!
Make friends with someone knowlegable, look at all the cars you can, and listen to all of the horror stories. Don't get in a rush!
TIMINATOR