Never heard of hub centric ones, cos surely that would have to be tailored to your exact hub size and even wheels with the exact same PCD and offset will have a different size actual mounting face even if its just a couple of mm?
Anyway the rule is dont buy cheap spacers. Always buy German when it comes to spacers cos theyve gone through TuV testing and wont unbalance your hubs too much. H&R and Eibach make quality spacers designed specifically for each application, ie theyre not the universal ones with like 13 holes in them to fit every car in the world.
17mm each side is a serious job. What you doing, a wide arch kit? It might mess up your handling a bit, and wear your suspension a lot quicker. I think Eibach or H&R both do 10 or 15mm spacers though. Ive got 5mm each side to clear my brake calipers and they run fine.