Adding a visual upgrade that has a higher rating than the one it replaces will rank the player's car higher within the Star Rating system. Points will be removed for installing a lower rating part or removing a part. In the first Underground, the Star Reputation system goes up to 5 stars, and has been increased to a 10 star rating in Underground 2. Unique parts add a higher star rating than any regular visual upgrade of the same category.
High Star Ratings are required for unlocking magazine cover opportunities and unique upgrades in the first Underground. In Underground 2, they are required for unlocking DVD cover oppurtunities as part of sponsor contracts.