There are a few methods to launch backups on GC:s without a chip. AFAIK the best one is using SDLoader with a SDGecko or equivalent, but that's still far from perfect compatibility wise. I'd go with a chip if I were you.
Got my hands on an as good as new GC, ordered a XenoGC v2.0, and installed it a few days ago. So far it works perfect, but then again, haven't tried too many games in the few days I've had my GC. The only downside I've found yet is that it's quite hard to install it the way the XenoGC people suggest, by soldering it directly to the DVD drive's controller board. I'm definitely no newbie when it comes to soldering, and I really had to use my creativity to avoid shorts, cold solders, etc. If you go with this chip, I recommend you to do some type of wired installation instead, cover the chip with shrink tube, electrical tape or something like that, and just put the chip between the controller board and the metal sheet that protects it. If you do a wired installation, it's way easier to remove the chip later if you want to aswell.
The screws keeping the case together got special heads. I've got the Shinobii Console Toolkit which contains the needed tool, perhaps those kits are still available, but a quick and dirty method if you can't get hold of one is to just melt the tip of a plastic pen or something, push it down into the screw hole and let the molten plastic stiffen around the screw head. Then unscrew the screw. If you're careful you can reuse your homemade tool for the next screw. You can replace those special screws keeping the case together when you're putting it all together again, just in case you need to open the GC later.
Other than that the disassembly is really easy, once inside the case there are only regular Philips screws.
