Sorry I can only provide limited information, my friend does all my 360 flashing so I only know the basics regarding that.
Anyway before Christmas I had a flashed Hitatchi Xbox 360 which was great, until it suddenly died with the 3 red lights (Scared the hell out of me when it happened, right during one of those weird moments in COD3!)
Bought a second hand Xbox and got my friend to flash it, this time a Samsung. Problem is disk reading is now quite loud (Whistling in some cases!) but the main problem is often the drive suddenly stops reading a backup game and then takes a few seconds to pick back up resulting in jumpy FMV/sound. I know the games are not the problem as these are of my original, mint condition, games.
I am using Verbatim MKM001 and CMC Mag D01 media, both were fine on the Hitatchi and are fine on the Samsung apart from the moments when it decides to stop reading!
The problem is annoying me because it dosen't happen every time, only when it decides to!