What are good upgrades for a 2 stroke dirt bike?

I'm getting my first dirt bike soon, a 125cc 2 stroke, but want it to be quite fast and upgraded. What parts should I upgrade which are relatively easy to do, cheap or work really well? Anything you think I should change to improve performance. Take a look at my other dirt bike questions too! Thanks.

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia…).