it is easy enough to do yourself and you really should learn how to do it. I could not put a number on the performance increase, but it is something you would notice and it is worth it. Here is a link to the Park tool repair site. Check out this site to learn how to do a lot of maintenence and repairs to your bike. Knowing how to do some simple adjustments and repairs can save you a lot of time, money, and agony. Good luck.
how to replace tire/inner tube