Could not find any suggestions online- my Mac is currently stock. Wanting a stable OS with good performance. No plans to take it online.
If there is a good reason for me to upgrade RAM etc that isn't expensive I'd be willing
So it has 32MB of RAM? I'd probably go with 8.5 or 8.6. The Kanga should be able to run any OS it could officially run fine provided it has enough RAM, even 9.1. Not sure how well OS 9 would run on 32MB though... It's really up to you. The best OS is the OS that best suits your needs while also performing well enough for pleasant use.
It uses a proprietary RAM card unfortunately. It may be the same type as the 3400, not sure. It will be a bit pricey for sure, especially if you want it maxed. My 3400c/200 (which has basically the same design) has 48MB, which is enough for what I do to it, although it would be fun to max it out and try to run OS X on it for fun. Having more is a nice to have, but really is only necessary if you want to run OS 9 or hack OS X onto it with XPostFacto.
That would be just like Apple, the 5300, 3400 and G3 Kanga (which all use the same "style" of RAM card) not being cross-compatible because they used slightly different chips or a slightly changed connector...
I’d say go with 8.6 at 32MB of RAM. Should run great on the G3 CPU. I agree with @Byrd , 8.6 improved upon 8.5 from a performance standpoint, plus added some nice little updates. If I recall correctly, many apps of the era had a minimum requirement of 8.6 due to Carbon support or something along those lines.
If you can get to 64MB or more of RAM, then 9.1 would also be a good option.
8.6 also introduces – I think – the Mac OS Nanokernel, which supposedly implements some form of preemptive multitasking and improved multiprocessing support, which is pretty much wasted because applications need to be explicitly written to support it, otherwise it will just run in the cooperatively multitasked "blue task," which only executes on the first processor in a multiprocessor system, so one will likely see zero benefit, only some extra overhead.
DISCLAIMER: It's late and I'm tired, so I may be completely wrong here, so do your research and don't just take my word for it!
I remembered that someone posted a link to a list of software that supports Apple's somewhat weird (by modern standards) multiprocessing setup somewhere in the past year or so (I think this was post-crash, so it's probably still around somewhere). Much of it predates 8.6 and its preemptively multitasked nanokernel, however.
This is of zero use on a Kanga of course, but I thought I'd mention it for educational purposes.
8.6 or 9.1 are the best choices for it depending on what you want in an OS, and what else you have. i have two 9.2.2 machines...but only one 8.x machine. I am currently awaiting news on a source for 3400/Kanga Ram, both use the same ram card just some early ones do not work properly due to speed issues.
Interesting, I read somewhere that Kanga can support OS X, though it would be via an app called xposit something.. I believe it could only support up to Panther or Jaguar ? I never owned a Kanga myself, but certainly it would be cool to see OS X on it.
The app is XPostFacto, and per the documentation a Kanga would run Panther "acceptably" with the exception that sleep mode and battery monitoring won't work. Since the Kanga is a G3, it would probably run Tiger through XPostFacto as well, though good luck to the brave soul who would try. Even maxed out at 160 MB, that'd be quite a churn.
Oh, yeah that was it ! I forgot somewhat the name of that app. I don't own a Kanga, but just wanted to know what version of OS X it can support. I do have Sorbet Leopard on the Pismo, it doesn't really work well though.