I have a 2003 and I'm not very good when it comes to working on bikes. Im trying to learn but I'm only 18. I recently traded my stock pipes with dan moto pipes (which I love) and got a K&N air filter. When i downshift there is always backfire which I'm not sure is a bad thing or not. Also the bike is really laggy until about 3k rpms which didn't happen before the new pipes. I know that my bike is lean because the pipes and i don't have a pc3. But is this bad for it? I don't have money for a pc3 because I'm a broke college student but i don't want to ruin my bike by running it too lean. I was just wondering if this is bad for it. I spend a lot of money on this bike and I just don't want anything ruined. what do you suggest?