I just got the Tavor. Though I'm probably not the best one to give you any feedback on it, as it's my first AEG, and have only played in 1 game with it. (will be 2 tonight)
Although I have disassembled the entire thing (haven't taken apart the gearbox, but pulled the gearbox out).
I have modified it a bit;
Removed the dummy switch on the forward grip and put it a real one and wired it to a jack on the opposite side so I can plug my flashlight and laser into it.
Filed down the corners of the empty space behind the battery compartment so that the battery can slide in further and make room for the plugs.
Put a G&G Silencer on it. It is a 14mm Clockwise Thread.
Put some Dense Crafting Foam (not spray foam, the green stuff you buy in sheets) in the body in a few places to quiet things down a bit.
Drilled out the Iron Sight hole so its a bit bigger. (the hole in it from stock is the size of the smaller hole on AR-15/M4/M16 type Sights)
I plan on making a review of the gun when I'm finished with everything I want to do. I'm just about there, I might make one or 2 more changes still. But if you have any questions or would just like to take a look at it some time, let me know.