Zodd:
No bonuses, though I did use the 'difficult' level instead of the default 'medium' level. I've got eight AI empire opponents and a handful of neutrals. One less neutral than before, though, since I assimilated one.
I started literally in the corner of the map with ONE warp point out, and the system leading out to the rest of the quadrant was occupied by the neutral. I managed to pass through for a while but when relations got difficult I had to defeat him to get unrestricted access. I built 300 medium troops and invaded his homeworld. Now I have methane breathers to supplement my oxygen breathing original race. I'm up to 4th in the ranking now. The AI is just not as focused as a human and I guess it never will be, so you can almost always beat it in a single system if you work at it.