Any outgoing link is a negative score, and any incoming link is a positive score.
So linking to a relevant site will provide the recipient with better search results. The question of whether you should have outgoing links should not be constrained by your search results - but more about being a useful resource to your visitors.
The more useful your site, the more you will get inbound links, which will increase your search performance.
But you don't have to wait around for this - contact your suppliers and get them to link to you.