There are a million and one posts to search on this, but my opinion is only from what I have on my 93. I have the Wolfe Racecraft, through the floor connectors on mine. You have to cut through the floor and are not that good of an idea for a newbie do it yourselfer, but they are very rigid. They are quite possibly the stiffist connectors possible. Anyways, I also like the looks of the Competition Engineering from Summit. This is just my 2cents. Do some searches though, you can learn more than you want.
Maximum Motorsports makes some great SFCs, as far as installing you just have to make sure the suspension is loaded like being on a drive on lift when you install them, I also put 10 Pound bags of ice on the floor up front while welding so my carpet would not burn.
I seocnd the comment regarding the wolfe racecraft subframes as I have them on my car..they are through the floor though and will require some interior removal and some kind of experience...my car had the competition eng bars on it when I first got and they were real nice fit though. I would look at those or wild rides or maximum motorsports makes killer products...
Running the FL Maximum Motorsport SF connectors on my '92 notch. Very solid pieces and I can't imagine needing anything more substancial for a mostly street car.