1. Will online play work and will it affect my Wii? Can Nintendo detect the chip?
Yes you can go online with it and it will not affect the wii and nintendo can't detect the chip.
2. How often are updates and do I NEED to get them?
The D2sun V3 does not have the disk updatability feature, it uses jtag updatability and so far no updates are needed. The company said that they would make one when needed. But the current firmware it is on right now will work on all the future games.
3. (I have an NTSC-U Wii) Can I play all PAL games (backups) without problems?
Remember, every chip has only partial region free support so u might have to region patch some games for it.
Extra Information: When u install the d2sun v3, u have to make sure ur switches on it are correct which depend on ur chipset. There is a small sticker on the switches that u can slowly peal off. Then use a sharp knife or a scalpel to put the correct switch settings on it. I would not recommend installing the extra switch that comes with ur chip which enables u to turn it on and off simply because it makes the wii unappealing and if the wii falls or the switch breaks through the usb or sd card drive, u might have a problem there. The chip will be on like default so don't worry. My words might make u anxious about getting the chip but don't worry, installing it is actually way too easy for me and i was a beginner.
Where u can get the chip: I got mine for a great deal at modchipcentral.com presoldered and came with a free triwing screwdriver and a ribbon cable and the extra switch for the low price of 65 dollars. It was an amazing deal!
I hope this helped!!!!