So is it safe to assume the US box was identical minus the stickers?
Yes, most of the boxes released later on were the same except for the barcode sticker, and the round sticker on the front the says "directives en francais" Also, instead of having a second full color manual in french, they had black and white fold out instructions in french. And no french on the back of the box, whereas earlier releases had french and english on the back of the box. I think it was a cheaper more cost effective solution for them to just use the same box and slap the "directives en francais sticker" on there and throw in the french fold out instructions.
as for the other sticker that says the game must be used with turbo booster, could be that it was a quick fix for them to put the stickers on if the game infact had a glitch. Or i'm thinking it could have been intentional on their part to make u buy the turbo booster. The sound is pretty cool on this game and does sound enhanced compared to other games.