I'm waiting for ioquake3's release; right now I think they are all working on the mac port because of SDL.
Single player does have its requireements, but not as much as multiplayer like urban terror; theirs is hunkmegs 512 zonemegs 128.
I'm running single player with hunkmegs at 128 and zonemegs at 32 and rarely running into hunk alloc errors, so probably I'll double the requirements if you're gonna load up 20 bots single player on your local machine and play a client. So I guess you'll need about 512mb.
I've been all about optimizations. With or without the bots, the requirements to run a server actually are lower than what they were with the last release, I'm just stress testing stuff now.
I don't think people are gonna load up 20 bots to play a single player game, but if they do, it'll run with specs we ran years ago.
There's a big changelog I wrote for the release, and I'm working on an installer now too, as well as an auto-updater. I'm only gonna release 5 maps; I'd release more but I gotta dig up the sources for a lot of them, and all older maps will work too... I removed the dom checkpoint checks.