heres the deal....I'm entering my 4th year teaching, but up until now, I haven't been the main instructor. My line has some quality players, but like a lot of high schoolers, they think they're way too good for the line. I'm pretty well liked with these kids, and I don't want to lose that.

How can I manage their egos without coming across as a complete penis?

I would have one on one conversations with them. Tell them what you expect from them and make sure they're on board with what you want to accomplish. Let them know that they'll be judged as a group and not individuals. Nobody wants to be the bad guy but sometimes a kid with an ego needs to be brought back to earth. Tell them you need their help working with the younger, less-experienced players and making sure things are progressing.

I've had several young players in the past with major ego problems and it can be tough to deal with. If a student in my line ever said he was too good for the group then I would have no problem telling him to find another line to play with. He/she is more than welcome to find a corps or WGI line to join. One kid with a big head can make for a long season.

A good attitude is the most important character quality in any drummer. No one likes to work with a cocky jerk. You seem like a person that is concerned with character. I think the best thing you can do is model & teach that to your kids. You will rub off on them in time. Push them past their talent level to show them they still have room to grow possibly. I think you are on the right track man, just show them the right way. Give them some of that drum & bugle corp type character stuff. Don't be to concerned if they like you. Don't be a turd but show them you mean business & you are there to educate them in music. Just keep telling yourself that you are a music educator & that is your job. They will respect in the long run. Good luck man... I have faced the same kinda stuff too, just keep your focus.

what i did is i got all of them together and gave them the pride speech, about having pride in the program that they are in and that there is not one drummer here that can't be replaced nor would i want to replace. but i have found when you instill a sense of pride in them the egos tend to go away

I would always either make their music harder the next day to keep them either occupied on learning and teaching the others, or it would put them in their place and they would learn they arent really all that.