Okay so If root I cant update my phone?

I have been using Myn's 2.2 RLS5 with Netarchy Toastmod 4.2.1 Kernel and have not had a single issue in over a week. I know you are failrly new to ROMS and flashing, so I would get use to flashing the ROMs first, then you can start reading up on some of the other Kernels that are out there. There isn't much to flashing a Kernel, it's a lot like flashing a ROM. You can get all the ROMs and Kernels you want here:

EVO 4G Android Development - xda-developers

If you have questions, just ask. The guys in this thread are awesome and can get you out of just about any sticky situation.