Hes referring to car color, and no sorry there isn't an option for that. Server runners have an option of what car colors are used though (I think check serv config file).
The limits are possible to expand but you can't currently get around these limits. Expanding as I have been told can be possible by doubling GTASA's pools (doubling memory usage though) or some great streaming work.
When you get towards the redline ("dbg_pools 1") is you start crashing the editor either on load or while editing. I found a trick where, if you are close to red and are crashing, you can load a previous verison of the map with a few less objects (safely under limit), then load your latest map, and it shouldn't crash. You still run high risk of crashing while editing though. So, this is just to place a few final things when you're near the redlined limit!
I'm assuming you mean, if you use an IPL and overload it past the limits? I don't know, try to convert a large IPL>MAP using aerons tool (and copy+paste some sps/cps from another map file) and try it. I doubt it would work, the limits are GTA limits.
edit: out of curosity I tried this. It does work. I'm not sure how stable this would be with masses of objs in same place.
Knowing this works however, you could combine multiple map files. I tried with 8lap wallride (which rides the limits). It works in server, but after playing a shortwhile it crashed MTA.