Your best bet is to look for anything with these specs...
16x6.5" 5x100 bolt pattern +55 offset.
Here's what I do sometimes
Go to http://www.tires.com and search for wheels for different cars. Since Discount tire lists all the wheel information diameter, width, bolt pattern, offset you can (through trial and error) find out what other cars use that will match. The wheel data is under the description and looks like this.
16X7 5-100 35S
The letter on the end refers to their color code in this case it is silver. This example is from a 2002 jetta. The offset is different than the subaru. Keep in mind that wheel width is related to offset. When the width changes so should the offset to maintain proper wheel fit.