I recall reading somewhere a long time ago that if you use a N64 Gameshark on your American system and put a Japanese game on top of it, you'll be able to play by skipping the cheats and going straight to the game. It makes sense to me, since the only thing keeping Japanese games from working is the different shape, and since the GS doesn't have those tabs, they'll fit just fine. However, I was thinking about importing something and I thought to myself "I should check again to make sure it'll work!" and I have been unable to find anything on it besides a few comments on YouTube videos, which I don't really trust.
I'd like to avoid cutting out the tabs inside the system, as it didn't work too well when I did that to my SNES and I don't have the correct screwdriver to take it apart to do it properly.

So if anyone can confirm the Gameshark thing, I'd be very grateful!