When i wass playing call of duty modern warfare it crashed couple of times during all of my game passing (it was trimmed with nds tokyo trim), but this could be the fauld of m3simply or microsd (but who knows).
It possibly could've been a bad dump/corrupt ROM.
As for the NDSTokyoTrim question:
-It is pretty much the best Trimmer out there
-Trims the most space possible without breaking Wi-Fi/Download Play
-Trims very fast, and efficient
-Batch trimming, you can trim all your ROMs at once (very convenient)
-Eye Candy
-Runs on All OS's, I believe.
~Nero