These displays are designed for a Uno. They work very well on a Uno.
If you use a Mega, the TFT will be 2.5x slower than a Uno. You must use Software SPI for the microSD. e.g. with the SdFat library.
Personally, I find the SdFat library is not as reliable to use as the regular SD library that comes with your Arduino.
Since Uno clones are so cheap, I suggest that you use your display with a clone instead of a Mega2560.
From my point of view, I look forward to hearing whether 0x9320 or 0x9331 gives a better picture.
David.