I just noticed this, but, you're not measuring that backspace correctly. Backspace is measured from the outside lip to the wheel mounting surface, not from the shoulder where the tire mounts. The backspace on those wheels is probably 4.25".
How wide are those rims? Are you sure they're factory? Because I don't think any of the factory 14" SBP rallye's would have 4" of backspace, let alone 4.25". The widest factory SBP rallye's would be 14x5.5, and they wouldn't have a 4" backspace.
A 15" wheel should solve the issue based on where your contact is, yes.