I spent a pretty long time looking for rims, and there is a world of difference between the size you measured to fit and what the wheel makers offer. Same goes for tires.
Here's what happened for me : at first, I wanted 17" American Racing Torque Thrust IIs, as wide as possible (9.5" on the rears). Not one of them would quite fit or have the width I wanted.
Then I started checking what kind of tires would fit, and I had to rethink everything again. I ended up with custom-made Forgeline wheels.
19x9.5 with 5.5 BS works fine in the rear for me. 19x8.5 with 5.25 up front (I have a slightly larger front-end than stock with the AlterKtion engine cradle, so I took a bit more BS, otherwise 4.75 would have been good).
For 17x9.0s with 5"BS, you can find several steel designs by Cragar (those will not be hub-centric), you can also find some aluminum designs like the Classic 5 by Team-3. Wheel vintiques have several models they can do with custom BS - including the ugly enlarged rallye.
With 17" rims, you have a little bit more flexibility than I have, and you may be able to install 275s on 8.5" wide wheels.
But make sure you find the tires first.
The ideal size in 275 for 17" tires is 275/50R17 (close to the same diameter as the OEM wheels).
I didn't not find a single tire available in that size. Some in 55 series (mostly truck tires), not a single one in 45.
On the other hand, a search for high-performance passenger car tires in 275/45R18 brings on some good ones (Bridgestone RE50s, Continental ContiSportContact2 & 3, Goodyear Eagle F1 GS-D3).
Don't get trapped needing a tire which doesn't exist.
If you really want to go wide, you may have to aim for 18" (that's exactly why I ended up buying 19" wheels)