I ended up sending my Z2 to Sanyo three times in all to address non-uniform color. On the first trip they did nothing. On the second trip they replaced the light bulb and this lessened, but did not cure the problem. On the third trip they changed the LCD panels. this did not fix the non-uniform color, but did introduce massive vertical banding that I did not have before. I was able to tweak out 80% of the VB in the service settings, but my point to you is that changing the LCD panels may or may not solve your VB problem and it could come back worse.
Tom
Tom