new head unit!

new head unit!

I recently added a new head unit to my rolla. I bought the Pioneer Premier-550.

Right now I'm testing it with the stock speakers to see how my head unit sounds.
I'm planning on getting new speakers and maybe adding a 12' box. You guys have any recommendations on the quality of speakers I should get in order to get the best performatnce out of my head unit? Do you guys think I made a good decision on purchasing the Pioneer Premier-550 headunit?

Also btw, I have a 03-04 stock head unit for sale ( cassette included ). I'm selling it for about 70 dollars + shipping and handling...e-mail me or AIM me.