If it's anything like a Lite, you'll have to partially disassemble the top half of the shell, maybe even nick off a few annoying plastic tabs (apologies if you already knew this in advance). I'm not going to consider swapping mine on my N3DS XL until I see plates I want. Personally I think Nintendo missed a large market by not doing custom plates for the XLs. I can understand not wanting to launch the standard-sized N3DS in North America, though. The regulars (and the DSi) of the same size were dropped like hot potatoes when XL versions came out. No real money to be had in it, though they did lose some minor sales to people doing imports because of it. Anyway, point being that I find the XL's lack of custom plates to be a huge miss in revenue for the Big N, especially outside of Japan.