I decided to remove my quad shocks, rather than use spacers.
As the other guy said, spacers put extra strain on the lugs.
I don't know if hub-centric spacers really help, either. Even with hub-centric spacers, I believe that most of the car's weight still rests on the lugs. It's an ongoing debate, but most authoritative sources I've read, say that most of a car's weight rests on the lugs, not on the hubs. One way think about it: How tight are the hubs, and how tight are the lugs nuts when fully tightened? The lug nuts are much tighter than the hubs, therefore I think that most of the car's weight rests on the lug nuts, and therefore on the lugs.
I'm running 15x8 rims, with 275/50/15 Nitto drag radials. The big tires wouldn't fit with the quad shocks, so I removed the quad shocks. I also used a hammer to pound in the lower lip of my inner fender wells, just for a little extra room.
Just driving around town, I don't notice any major problems, with the missing quad shocks. I'm going to get aftermarket
control arms and bushings, to minimize the possibility of wheel hop, and to tighten up the
suspension.
Anyway, my 15x8 rims have 5.5 inch backspacing. Backspacing is the distance between the axle-wheel interface and the back of the wheel (the part of the wheel closest to the car). The larger the backspacing, the further inward the wheel will be.
However, there's a big difference between 15 inch rims with big fat tires, and 17 inch rims. The 17 inch rims have more clearance toward the center, because of the larger radius.
And, of course, it depends on how wide the tires are. And the brand of tires. Nittos run narrow, and BFG run wide, or so I've heard. It also may even depend on the rim brand, or maybe not. I'm not sure about that.
If you have too much backspacing, the wheels will hit your inner fender wells, and of course the quad shocks, if you keep your quad shocks. If you have too little backspacing, the wheels may rub on the upper outer lip of the fenders, when your wheels hit a bump, or when you turn onto a steep driveway (in other words, whenever the wheel is deflected upward for any reason).
Spacers are a "crutch" for improper backspacing, in my opinion.
You should do lots of searches.
I'm not really sure what the best backspacing is, for 17x9 rims, but I'm sure there are lots of posts on that subject.
My guesstimate would be the 5.95 inch backspacing, so that maybe you won't have to remove your quad shocks, but that's only a wild guess.
Again, I would avoid spacers at all costs.