Using wheels made for a different stud pattern is a no-no. There are probably plenty of people who get away with it but you end up putting stress on the wheel studs that were never intended.
The wheels are machined with a tapered seat that is at the specific diameter, and using an alternate wheel that does not have the same diameter means the retaining fasteners (lug nuts) are being loaded on only part of their seating surface (ie. not on the full diameter of the nut) and the result is the load concentration on only part of the nut and wheel can lead to failure of one or the other, or both--my bet would be the wheel would have problems, especially if they are aluminum, but regardless of material, the fit is not correct.
Also, if the wheels you are thinking of using have a different hub center dimension, they either will not fit or if the hole in the wheels is larger, you will not get the normal support at the hub that the factory designs into the OE wheels and end up placing even more load on just the studs.
This is especially important on FWD cars that have both drive and steer duties, unlike a RWD car.
Just my opinion, but this is not a good plan. Don't jeopardize your car with this idea. Sorry to be a boo-bird...
114.3 and 115 ARE two different bolt patterns (referred to as PCD). Many people put 114.3 wheels on their GM cars, and several wheel and tire people say it's OK except for racing. I however, would not do it. There are a few genuine 115mm PCD wheels available. When I designed wheels for Enkei several years ago, I had them make me a custom set of 115mm wheels at the factory (18x7 Enkei Shurikens). Many aftermarket wheels are lug centric (centered by the wheel studs vs. centered on the hub), so I would definitely not use any 114.3 wheel that was not centered by the hub. Additionally, I would recommend getting hub ring adapters to fit your hub, instead of running the wheels with oversized hub bores ( as many people do), which can cause high speed vibration.