The purpose of using larger wheels/tires is mainly to increase the contact patch on the road. This is why FWD drag cars have a larger setup in front and RWD cars have a larger setup out back.
In addition, you could not reuse the same set of wheels for a S14 later on because the S14 (being a RWD car) has a different offset compared to a FWD Camry. The bolt circle might match, but the offset does not. You might want to consider spacers if you really wanted to reuse the wheels on the S14, but you will be spending more money to get spacers.
Doing the proposed setup will defeat your purpose overall, because at the end, you will be spending money you really do not have to.
Your setup will mess up your handling, then you will be forced to end up replacing the wider pair with what you should have bought in the first place.... :disappoin