The holley pro flo will mount right to your manifold, and is easy to tune, but I've heard a ton of gripes about it, and would be a little leary. I think the price is under $1000.

A Camaro/corvette 1985-86 TPI or 1984crossfire injection setup from GM can be found on ebay or at the junkyard, and will bolt right to your motor. you will have to tap a boss for a knock sensor. These systems work good with compression between 8.5:1 - 9.5:1 in stock form. They are cheap and pretty reliable, with moderate to good performance. I have this conversion on one of my non Volvo cars.
It took me 3 days to get the wiring figured out, but worked well.