Taxes Paid generally means your have done what is also referred to as a Stage 1 conversion on the bike. This is commonly know to be, more free flowing (louder) pipes, a more free flowing air cleaner and then either a carb rejet, or EFI remapping.
The reason for the term "Taxes Paid" is because when you make these improvements to your ride, you are basically undoing the regulations forced on the moco by the EPA. Therefore, since you have to spend money to get your bike to run properly, and it's due to Government regulations, that money is referred to as a "Tax".
I'm not trying to be a smarta$$ but since you are a new user I'm offering a tip. At the top of the page is a "Search" button. If you click on it and type in "taxes paid" you will find the answer to your question.