"Performance mod" limits the responses to some degree. In that context, I'd have to say stickier tires would inspire more confidence in the corners.
If you want to expand the field to "any" mod, I'd have to say (for me) lowering the bike made it perfect... Not only for mounting and paddling backwards, but feeling more planted in the corners, and giving it (IMHO) more flickability in general. Second best mod, for me, is the seat (I put a Sargent on it). Comfort on the bike can determine whether you love or hate your ride, and the Sargent makes a world of difference.
2015 Versys 650 Pearl White
[space holder for farkles...]