How important is actually using the sponsor's product versus just displaying their logo?

Authenticity is critical - if you're not actually using the product, it's hard to represent it legitimately. For many technical sponsors like K&N and NGK, having products 'in use' was a requirement for sponsorship. This authenticity helps you genuinely promote the product because you can speak from experience, and it shows in how you represent the brand. While some consumer products don't need to be 'in use' the same way (you might not use Tide on your race car), for performance parts and technical products, authentic use is essential to being a credible brand ambassador.