Two products with just one charactar difference, how deal with it?

We have two products: System M and System M+. Right now, System M is always on top of the ranking, even when i search for System M+. How can i deal with this? I want System M+ on top when I search for System M+

The search index ignores special characters by default. You’ll want to explicitly tell the index you want to include the plus sign (+), similar to what they do with the period (.) in this post: